diff --git a/.changesets/add-instrumentation-for-streaming-rack-responses.md b/.changesets/add-instrumentation-for-streaming-rack-responses.md
new file mode 100644
index 000000000..6308665da
--- /dev/null
+++ b/.changesets/add-instrumentation-for-streaming-rack-responses.md
@@ -0,0 +1,21 @@
+---
+bump: "minor"
+type: "add"
+---
+
+Add instrumentation for all Rack responses, including streaming responses. New `response_body_each.rack`, `response_body_call.rack` and `response_body_to_ary.rack` events will be shown in the event timeline. This will show how long it takes to complete responses, depending on the response implementation.
+
+This Sinatra route with a streaming response will be better instrumented, for example:
+
+```ruby
+get "/stream" do
+  stream do |out|
+    sleep 1
+    out << "1"
+    sleep 1
+    out << "2"
+    sleep 1
+    out << "3"
+  end
+end
+```
diff --git a/lib/appsignal.rb b/lib/appsignal.rb
index eb2e024ee..cc39a4e1e 100644
--- a/lib/appsignal.rb
+++ b/lib/appsignal.rb
@@ -305,5 +305,6 @@ def collect_environment_metadata
 require "appsignal/integrations/railtie" if defined?(::Rails)
 require "appsignal/transaction"
 require "appsignal/version"
+require "appsignal/rack/body_wrapper"
 require "appsignal/rack/generic_instrumentation"
 require "appsignal/transmitter"
diff --git a/lib/appsignal/rack/body_wrapper.rb b/lib/appsignal/rack/body_wrapper.rb
new file mode 100644
index 000000000..f76947304
--- /dev/null
+++ b/lib/appsignal/rack/body_wrapper.rb
@@ -0,0 +1,161 @@
+# frozen_string_literal: true
+
+module Appsignal
+  # @api private
+  module Rack
+    class BodyWrapper
+      def self.wrap(original_body, appsignal_transaction)
+        # The logic of how Rack treats a response body differs based on which methods
+        # the body responds to. This means that to support the Rack 3.x spec in full
+        # we need to return a wrapper which matches the API of the wrapped body as closely
+        # as possible. Pick the wrapper from the most specific to the least specific.
+        # See https://github.com/rack/rack/blob/main/SPEC.rdoc#the-body-
+        #
+        # What is important is that our Body wrapper responds to the same methods Rack
+        # (or a webserver) would be checking and calling, and passes through that functionality
+        # to the original body. This can be done using delegation via i.e. SimpleDelegate
+        # but we also need "close" to get called correctly so that the Appsignal transaction
+        # gets completed - which will not happen, for example, when #to_ary gets called
+        # just on the delegated Rack body.
+        #
+        # This comment https://github.com/rails/rails/pull/49627#issuecomment-1769802573
+        # is of particular interest to understand why this has to be somewhat complicated.
+        if original_body.respond_to?(:to_path)
+          PathableBodyWrapper.new(original_body, appsignal_transaction)
+        elsif original_body.respond_to?(:to_ary)
+          ArrayableBodyWrapper.new(original_body, appsignal_transaction)
+        elsif !original_body.respond_to?(:each) && original_body.respond_to?(:call)
+          # This body only supports #call, so we must be running a Rack 3 application
+          # It is possible that a body exposes both `each` and `call` in the hopes of
+          # being backwards-compatible with both Rack 3.x and Rack 2.x, however
+          # this is not going to work since the SPEC says that if both are available,
+          # `each` should be used and `call` should be ignored.
+          # So for that case we can drop by to our default EnumerableBodyWrapper
+          CallableBodyWrapper.new(original_body, appsignal_transaction)
+        else
+          EnumerableBodyWrapper.new(original_body, appsignal_transaction)
+        end
+      end
+
+      def initialize(body, appsignal_transaction)
+        @body_already_closed = false
+        @body = body
+        @transaction = appsignal_transaction
+      end
+
+      # This must be present in all Rack bodies and will be called by the serving adapter
+      def close
+        # The @body_already_closed check is needed so that if `to_ary`
+        # of the body has already closed itself (as prescribed) we do not
+        # attempt to close it twice
+        if !@body_already_closed && @body.respond_to?(:close)
+          Appsignal.instrument("response_body_close.rack") { @body.close }
+        end
+        @body_already_closed = true
+      rescue Exception => error # rubocop:disable Lint/RescueException
+        @transaction.set_error(error)
+        raise error
+      ensure
+        complete_transaction!
+      end
+
+      def complete_transaction!
+        # We need to call the Transaction class method and not
+        # @transaction.complete because the transaction is still
+        # thread-local and it needs to remove itself from the
+        # thread variables correctly, which does not happen on
+        # Transaction#complete.
+        #
+        # In the future it would be a good idea to ensure
+        # that the current transaction is the same as @transaction,
+        # or allow @transaction to complete itself and remove
+        # itself from Thread.current
+        Appsignal::Transaction.complete_current!
+      end
+    end
+
+    # The standard Rack body wrapper which exposes "each" for iterating
+    # over the response body. This is supported across all 3 major Rack
+    # versions.
+    #
+    # @api private
+    class EnumerableBodyWrapper < BodyWrapper
+      def each(&blk)
+        # This is a workaround for the Rails bug when there was a bit too much
+        # eagerness in implementing to_ary, see:
+        # https://github.com/rails/rails/pull/44953
+        # https://github.com/rails/rails/pull/47092
+        # https://github.com/rails/rails/pull/49627
+        # https://github.com/rails/rails/issues/49588
+        # While the Rack SPEC does not mandate `each` to be callable
+        # in a blockless way it is still a good idea to have it in place.
+        return enum_for(:each) unless block_given?
+
+        Appsignal.instrument("process_response_body.rack", "Process Rack response body (#each)") do
+          @body.each(&blk)
+        end
+      rescue Exception => error # rubocop:disable Lint/RescueException
+        @transaction.set_error(error)
+        raise error
+      end
+    end
+
+    # The callable response bodies are a new Rack 3.x feature, and would not work
+    # with older Rack versions. They must not respond to `each` because
+    # "If it responds to each, you must call each and not call". This is why
+    # it inherits from BodyWrapper directly and not from EnumerableBodyWrapper
+    #
+    # @api private
+    class CallableBodyWrapper < BodyWrapper
+      def call(stream)
+        # `stream` will be closed by the app we are calling, no need for us
+        # to close it ourselves
+        Appsignal.instrument("process_response_body.rack", "Process Rack response body (#call)") do
+          @body.call(stream)
+        end
+      rescue Exception => error # rubocop:disable Lint/RescueException
+        @transaction.set_error(error)
+        raise error
+      end
+    end
+
+    # "to_ary" takes precedence over "each" and allows the response body
+    # to be read eagerly. If the body supports that method, it takes precedence
+    # over "each":
+    # "Middleware may call to_ary directly on the Body and return a new Body in its place"
+    # One could "fold" both the to_ary API and the each() API into one Body object, but
+    # to_ary must also call "close" after it executes - and in the Rails implementation
+    # this pecularity was not handled properly.
+    #
+    # @api private
+    class ArrayableBodyWrapper < EnumerableBodyWrapper
+      def to_ary
+        @body_already_closed = true
+        Appsignal.instrument(
+          "process_response_body.rack",
+          "Process Rack response body (#to_ary)"
+        ) do
+          @body.to_ary
+        end
+      rescue Exception => error # rubocop:disable Lint/RescueException
+        @transaction.set_error(error)
+        raise error
+      ensure
+        # We do not call "close" on ourselves as the only action
+        # we need to complete is completing the transaction.
+        complete_transaction!
+      end
+    end
+
+    # Having "to_path" on a body allows Rack to serve out a static file, or to
+    # pass that file to the downstream webserver for sending using X-Sendfile
+    class PathableBodyWrapper < EnumerableBodyWrapper
+      def to_path
+        Appsignal.instrument("response_body_to_path.rack") { @body.to_path }
+      rescue Exception => error # rubocop:disable Lint/RescueException
+        @transaction.set_error(error)
+        raise error
+      end
+    end
+  end
+end
diff --git a/lib/appsignal/rack/generic_instrumentation.rb b/lib/appsignal/rack/generic_instrumentation.rb
index 2599566e2..17f99c28e 100644
--- a/lib/appsignal/rack/generic_instrumentation.rb
+++ b/lib/appsignal/rack/generic_instrumentation.rb
@@ -16,7 +16,9 @@ def call(env)
         if Appsignal.active?
           call_with_appsignal_monitoring(env)
         else
-          @app.call(env)
+          nil_transaction = Appsignal::Transaction::NilTransaction.new
+          status, headers, obody = @app.call(env)
+          [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, nil_transaction)]
         end
       end
 
@@ -27,19 +29,30 @@ def call_with_appsignal_monitoring(env)
           Appsignal::Transaction::HTTP_REQUEST,
           request
         )
+        # We need to complete the transaction if there is an exception inside the `call`
+        # of the app. If there isn't one and the app returns us a Rack response triplet, we let
+        # the BodyWrapper complete the transaction when #close gets called on it
+        # (guaranteed by the webserver)
+        complete_transaction_without_body = false
         begin
           Appsignal.instrument("process_action.generic") do
-            @app.call(env)
+            status, headers, obody = @app.call(env)
+            [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, transaction)]
           end
         rescue Exception => error # rubocop:disable Lint/RescueException
           transaction.set_error(error)
+          complete_transaction_without_body = true
           raise error
         ensure
-          transaction.set_action_if_nil(env["appsignal.route"] || "unknown")
+          default_action = env["appsignal.route"] || env["appsignal.action"] || "unknown"
+          transaction.set_action_if_nil(default_action)
           transaction.set_metadata("path", request.path)
           transaction.set_metadata("method", request.request_method)
           transaction.set_http_or_background_queue_start
-          Appsignal::Transaction.complete_current!
+
+          # Transaction gets completed when the body gets read out, except in cases when
+          # the app failed before returning us the Rack response triplet.
+          Appsignal::Transaction.complete_current! if complete_transaction_without_body
         end
       end
     end
diff --git a/lib/appsignal/rack/rails_instrumentation.rb b/lib/appsignal/rack/rails_instrumentation.rb
index 8de088cd1..6fa30c4ee 100644
--- a/lib/appsignal/rack/rails_instrumentation.rb
+++ b/lib/appsignal/rack/rails_instrumentation.rb
@@ -16,7 +16,9 @@ def call(env)
         if Appsignal.active?
           call_with_appsignal_monitoring(env)
         else
-          @app.call(env)
+          nil_transaction = Appsignal::Transaction::NilTransaction.new
+          status, headers, obody = @app.call(env)
+          [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, nil_transaction)]
         end
       end
 
@@ -28,10 +30,17 @@ def call_with_appsignal_monitoring(env)
           request,
           :params_method => :filtered_parameters
         )
+        # We need to complete the transaction if there is an exception exception inside the `call`
+        # of the app. If there isn't one and the app returns us a Rack response triplet, we let
+        # the BodyWrapper complete the transaction when #close gets called on it
+        # (guaranteed by the webserver)
+        complete_transaction_without_body = false
         begin
-          @app.call(env)
+          status, headers, obody = @app.call(env)
+          [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, transaction)]
         rescue Exception => error # rubocop:disable Lint/RescueException
           transaction.set_error(error)
+          complete_transaction_without_body = true
           raise error
         ensure
           controller = env["action_controller.instance"]
@@ -45,7 +54,10 @@ def call_with_appsignal_monitoring(env)
           rescue => error
             Appsignal.internal_logger.error("Unable to report HTTP request method: '#{error}'")
           end
-          Appsignal::Transaction.complete_current!
+
+          # Transaction gets completed when the body gets read out, except in cases when
+          # the app failed before returning us the Rack response triplet.
+          Appsignal::Transaction.complete_current! if complete_transaction_without_body
         end
       end
 
diff --git a/lib/appsignal/rack/sinatra_instrumentation.rb b/lib/appsignal/rack/sinatra_instrumentation.rb
index ef88c0f7d..436b26c4d 100644
--- a/lib/appsignal/rack/sinatra_instrumentation.rb
+++ b/lib/appsignal/rack/sinatra_instrumentation.rb
@@ -42,7 +42,9 @@ def call(env)
         if Appsignal.active?
           call_with_appsignal_monitoring(env)
         else
-          @app.call(env)
+          nil_transaction = Appsignal::Transaction::NilTransaction.new
+          status, headers, obody = @app.call(env)
+          [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, nil_transaction)]
         end
       end
 
@@ -56,12 +58,19 @@ def call_with_appsignal_monitoring(env)
           request,
           options
         )
+        # We need to complete the transaction if there is an exception exception inside the `call`
+        # of the app. If there isn't one and the app returns us a Rack response triplet, we let
+        # the BodyWrapper complete the transaction when #close gets called on it
+        # (guaranteed by the webserver)
+        complete_transaction_without_body = false
         begin
           Appsignal.instrument("process_action.sinatra") do
-            @app.call(env)
+            status, headers, obody = @app.call(env)
+            [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, transaction)]
           end
         rescue Exception => error # rubocop:disable Lint/RescueException
           transaction.set_error(error)
+          complete_transaction_without_body = true
           raise error
         ensure
           # If raise_error is off versions of Sinatra don't raise errors, but store
@@ -73,7 +82,10 @@ def call_with_appsignal_monitoring(env)
           transaction.set_metadata("path", request.path)
           transaction.set_metadata("method", request.request_method)
           transaction.set_http_or_background_queue_start
-          Appsignal::Transaction.complete_current!
+
+          # Transaction gets completed when the body gets read out, except in cases when
+          # the app failed before returning us the Rack response triplet.
+          Appsignal::Transaction.complete_current! if complete_transaction_without_body
         end
       end
 
diff --git a/lib/appsignal/rack/streaming_listener.rb b/lib/appsignal/rack/streaming_listener.rb
index 3a9da2f3c..a46644f25 100644
--- a/lib/appsignal/rack/streaming_listener.rb
+++ b/lib/appsignal/rack/streaming_listener.rb
@@ -16,7 +16,9 @@ def call(env)
         if Appsignal.active?
           call_with_appsignal_monitoring(env)
         else
-          @app.call(env)
+          nil_transaction = Appsignal::Transaction::NilTransaction.new
+          status, headers, obody = @app.call(env)
+          [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, nil_transaction)]
         end
       end
 
@@ -28,46 +30,35 @@ def call_with_appsignal_monitoring(env)
           request
         )
 
+        # We need to complete the transaction if there is an exception exception inside the `call`
+        # of the app. If there isn't one and the app returns us a Rack response triplet, we let
+        # the BodyWrapper complete the transaction when #close gets called on it
+        # (guaranteed by the webserver)
+        complete_transaction_without_body = false
+
         # Instrument a `process_action`, to set params/action name
-        status, headers, body =
+        begin
           Appsignal.instrument("process_action.rack") do
-            @app.call(env)
-          rescue Exception => e # rubocop:disable Lint/RescueException
-            transaction.set_error(e)
-            raise e
-          ensure
-            transaction.set_action_if_nil(env["appsignal.action"])
-            transaction.set_metadata("path", request.path)
-            transaction.set_metadata("method", request.request_method)
-            transaction.set_http_or_background_queue_start
+            status, headers, obody = @app.call(env)
+            [status, headers, Appsignal::Rack::BodyWrapper.wrap(obody, transaction)]
           end
+        rescue Exception => error # rubocop:disable Lint/RescueException
+          transaction.set_error(error)
+          complete_transaction_without_body = true
+          raise error
+        ensure
+          transaction.set_action_if_nil(env["appsignal.action"])
+          transaction.set_metadata("path", request.path)
+          transaction.set_metadata("method", request.request_method)
+          transaction.set_http_or_background_queue_start
 
-        # Wrap the result body with our StreamWrapper
-        [status, headers, StreamWrapper.new(body, transaction)]
+          # Transaction gets completed when the body gets read out, except in cases when
+          # the app failed before returning us the Rack response triplet.
+          Appsignal::Transaction.complete_current! if complete_transaction_without_body
+        end
       end
     end
   end
 
-  class StreamWrapper
-    def initialize(stream, transaction)
-      @stream = stream
-      @transaction = transaction
-    end
-
-    def each(&block)
-      @stream.each(&block)
-    rescue Exception => e # rubocop:disable Lint/RescueException
-      @transaction.set_error(e)
-      raise e
-    end
-
-    def close
-      @stream.close if @stream.respond_to?(:close)
-    rescue Exception => e # rubocop:disable Lint/RescueException
-      @transaction.set_error(e)
-      raise e
-    ensure
-      Appsignal::Transaction.complete_current!
-    end
-  end
+  StreamWrapper = Rack::EnumerableBodyWrapper
 end
diff --git a/spec/lib/appsignal/rack/body_wrapper_spec.rb b/spec/lib/appsignal/rack/body_wrapper_spec.rb
new file mode 100644
index 000000000..f263ce5bf
--- /dev/null
+++ b/spec/lib/appsignal/rack/body_wrapper_spec.rb
@@ -0,0 +1,220 @@
+describe Appsignal::Rack::BodyWrapper do
+  let(:nil_txn) { Appsignal::Transaction::NilTransaction.new }
+
+  describe "with a body that supports all possible features" do
+    it "reduces the supported methods to just each()" do
+      # which is the safest thing to do, since the body is likely broken
+      fake_body = double(:each => nil, :call => nil, :to_ary => [], :to_path => "/tmp/foo.bin",
+        :close => nil)
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).to respond_to(:each)
+      expect(wrapped).not_to respond_to(:to_ary)
+      expect(wrapped).not_to respond_to(:call)
+      expect(wrapped).to respond_to(:close)
+    end
+  end
+
+  describe "with a body only supporting each()" do
+    it "wraps with appropriate class" do
+      fake_body = double
+      allow(fake_body).to receive(:each)
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).to respond_to(:each)
+      expect(wrapped).not_to respond_to(:to_ary)
+      expect(wrapped).not_to respond_to(:call)
+      expect(wrapped).to respond_to(:close)
+    end
+
+    it "reads out the body in full using each" do
+      fake_body = double
+      expect(fake_body).to receive(:each).once.and_yield("a").and_yield("b").and_yield("c")
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect { |b| wrapped.each(&b) }.to yield_successive_args("a", "b", "c")
+    end
+
+    it "returns an Enumerator if each() gets called without a block" do
+      fake_body = double
+      expect(fake_body).to receive(:each).once.and_yield("a").and_yield("b").and_yield("c")
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      enum = wrapped.each
+      expect(enum).to be_kind_of(Enumerator)
+      expect { |b| enum.each(&b) }.to yield_successive_args("a", "b", "c")
+    end
+
+    it "sets the exception raised inside each() into the Appsignal transaction" do
+      fake_body = double
+      expect(fake_body).to receive(:each).once.and_raise(Exception.new("Oops"))
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect do
+        expect { |b| wrapped.each(&b) }.to yield_control
+      end.to raise_error(/Oops/)
+    end
+
+    it "closes the body and the transaction when it gets closed" do
+      fake_body = double
+      expect(fake_body).to receive(:each).once.and_yield("a").and_yield("b").and_yield("c")
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(Appsignal::Transaction).to receive(:complete_current!).once
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect { |b| wrapped.each(&b) }.to yield_successive_args("a", "b", "c")
+      expect { wrapped.close }.not_to raise_error
+    end
+  end
+
+  describe "with a body supporting both each() and call" do
+    it "wraps with the wrapper that conceals call() and exposes each" do
+      fake_body = double
+      allow(fake_body).to receive(:each)
+      allow(fake_body).to receive(:call)
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).to respond_to(:each)
+      expect(wrapped).not_to respond_to(:to_ary)
+      expect(wrapped).not_to respond_to(:call)
+      expect(wrapped).not_to respond_to(:to_path)
+      expect(wrapped).to respond_to(:close)
+    end
+  end
+
+  describe "with a body supporting both to_ary and each" do
+    let(:fake_body) { double(:each => nil, :to_ary => []) }
+    it "wraps with appropriate class" do
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).to respond_to(:each)
+      expect(wrapped).to respond_to(:to_ary)
+      expect(wrapped).not_to respond_to(:call)
+      expect(wrapped).not_to respond_to(:to_path)
+      expect(wrapped).to respond_to(:close)
+    end
+
+    it "reads out the body in full using each" do
+      expect(fake_body).to receive(:each).once.and_yield("a").and_yield("b").and_yield("c")
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect { |b| wrapped.each(&b) }.to yield_successive_args("a", "b", "c")
+    end
+
+    it "sets the exception raised inside each() into the Appsignal transaction" do
+      expect(fake_body).to receive(:each).once.and_raise(Exception.new("Oops"))
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect do
+        expect { |b| wrapped.each(&b) }.to yield_control
+      end.to raise_error(/Oops/)
+    end
+
+    it "reads out the body in full using to_ary" do
+      expect(fake_body).to receive(:to_ary).and_return(["one", "two", "three"])
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped.to_ary).to eq(["one", "two", "three"])
+    end
+
+    it "sends the exception raised inside to_ary() into the Appsignal and closes txn" do
+      fake_body = double
+      allow(fake_body).to receive(:each)
+      expect(fake_body).to receive(:to_ary).once.and_raise(Exception.new("Oops"))
+      expect(fake_body).not_to receive(:close) # Per spec we expect the body has closed itself
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+      expect(Appsignal::Transaction).to receive(:complete_current!).once
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect { wrapped.to_ary }.to raise_error(/Oops/)
+    end
+  end
+
+  describe "with a body supporting both to_path and each" do
+    let(:fake_body) { double(:each => nil, :to_path => nil) }
+
+    it "wraps with appropriate class" do
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).to respond_to(:each)
+      expect(wrapped).not_to respond_to(:to_ary)
+      expect(wrapped).not_to respond_to(:call)
+      expect(wrapped).to respond_to(:to_path)
+      expect(wrapped).to respond_to(:close)
+    end
+
+    it "reads out the body in full using each()" do
+      expect(fake_body).to receive(:each).once.and_yield("a").and_yield("b").and_yield("c")
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect { |b| wrapped.each(&b) }.to yield_successive_args("a", "b", "c")
+    end
+
+    it "sets the exception raised inside each() into the Appsignal transaction" do
+      expect(fake_body).to receive(:each).once.and_raise(Exception.new("Oops"))
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect do
+        expect { |b| wrapped.each(&b) }.to yield_control
+      end.to raise_error(/Oops/)
+    end
+
+    it "sets the exception raised inside to_path() into the Appsignal transaction" do
+      allow(fake_body).to receive(:to_path).once.and_raise(Exception.new("Oops"))
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+      expect(txn).not_to receive(:complete) # gets called by the caller via close()
+
+      wrapped = described_class.wrap(fake_body, txn)
+      expect { wrapped.to_path }.to raise_error(/Oops/)
+    end
+
+    it "exposes to_path to the sender" do
+      allow(fake_body).to receive(:to_path).and_return("/tmp/file.bin")
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped.to_path).to eq("/tmp/file.bin")
+    end
+  end
+
+  describe "with a body only supporting call()" do
+    let(:fake_body) { double(:call => nil) }
+    it "wraps with appropriate class" do
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect(wrapped).not_to respond_to(:each)
+      expect(wrapped).not_to respond_to(:to_ary)
+      expect(wrapped).to respond_to(:call)
+      expect(wrapped).not_to respond_to(:to_path)
+      expect(wrapped).to respond_to(:close)
+    end
+
+    it "passes the stream into the call() of the body" do
+      fake_rack_stream = double("stream")
+      expect(fake_body).to receive(:call).with(fake_rack_stream)
+
+      wrapped = described_class.wrap(fake_body, nil_txn)
+      expect { wrapped.call(fake_rack_stream) }.not_to raise_error
+    end
+
+    it "sets the exception raised inside call() into the Appsignal transaction" do
+      fake_rack_stream = double
+      allow(fake_body).to receive(:call).with(fake_rack_stream).and_raise(Exception.new("Oopsie"))
+
+      txn = double("Appsignal transaction", "nil_transaction?" => false)
+      expect(txn).to receive(:set_error).once.with(instance_of(Exception))
+      expect(txn).not_to receive(:complete) # gets called by the caller via close()
+      wrapped = described_class.wrap(fake_body, txn)
+
+      expect { wrapped.call(fake_rack_stream) }.to raise_error(/Oopsie/)
+    end
+  end
+end
diff --git a/spec/lib/appsignal/rack/generic_instrumentation_spec.rb b/spec/lib/appsignal/rack/generic_instrumentation_spec.rb
index 0fa0104b9..27ee99e82 100644
--- a/spec/lib/appsignal/rack/generic_instrumentation_spec.rb
+++ b/spec/lib/appsignal/rack/generic_instrumentation_spec.rb
@@ -50,7 +50,7 @@
       expect(app).to receive(:call).with(env)
     end
 
-    context "with an exception", :error => true do
+    context "with an exception raised from call()", :error => true do
       let(:error) { ExampleException }
       let(:app) do
         double.tap do |d|
@@ -58,8 +58,9 @@
         end
       end
 
-      it "records the exception" do
+      it "records the exception and completes the transaction" do
         expect_any_instance_of(Appsignal::Transaction).to receive(:set_error).with(error)
+        expect(Appsignal::Transaction).to receive(:complete_current!)
       end
     end
 
diff --git a/spec/lib/appsignal/rack/rails_instrumentation_spec.rb b/spec/lib/appsignal/rack/rails_instrumentation_spec.rb
index 481854b11..7937a4782 100644
--- a/spec/lib/appsignal/rack/rails_instrumentation_spec.rb
+++ b/spec/lib/appsignal/rack/rails_instrumentation_spec.rb
@@ -65,7 +65,8 @@ class MockController
 
     describe "#call_with_appsignal_monitoring" do
       def run
-        middleware.call(env)
+        _status, _headers, body = middleware.call(env)
+        body.close # Rack will always call close() on the body
       end
 
       it "calls the wrapped app" do
@@ -126,7 +127,8 @@ def run
           end
         end
 
-        it "records the exception" do
+        it "records the exception and completes the transaction" do
+          expect(Appsignal::Transaction).to receive(:complete_current!)
           expect { run }.to raise_error(error)
 
           transaction_hash = last_transaction.to_h
diff --git a/spec/lib/appsignal/rack/sinatra_instrumentation_spec.rb b/spec/lib/appsignal/rack/sinatra_instrumentation_spec.rb
index 279b45a9b..dc0387959 100644
--- a/spec/lib/appsignal/rack/sinatra_instrumentation_spec.rb
+++ b/spec/lib/appsignal/rack/sinatra_instrumentation_spec.rb
@@ -3,7 +3,9 @@
 
   module SinatraRequestHelpers
     def make_request(env)
-      middleware.call(env)
+      _status, _headers, body = middleware.call(env)
+      # Close the body so that the transaction gets completed
+      body&.close
     end
 
     def make_request_with_error(env, error)
diff --git a/spec/lib/appsignal/rack/streaming_listener_spec.rb b/spec/lib/appsignal/rack/streaming_listener_spec.rb
index 4b6d7fa82..e0cd81bf5 100644
--- a/spec/lib/appsignal/rack/streaming_listener_spec.rb
+++ b/spec/lib/appsignal/rack/streaming_listener_spec.rb
@@ -90,10 +90,11 @@
     context "with an exception in the instrumentation call" do
       let(:error) { ExampleException }
 
-      it "should add the exception to the transaction" do
+      it "should add the exception to the transaction and complete the transaction" do
         allow(app).to receive(:call).and_raise(error)
 
         expect(transaction).to receive(:set_error).with(error)
+        expect(Appsignal::Transaction).to receive(:complete_current!).and_call_original
 
         expect do
           listener.call_with_appsignal_monitoring(env)
@@ -101,64 +102,19 @@
       end
     end
 
-    it "should wrap the body in a wrapper" do
-      expect(Appsignal::StreamWrapper).to receive(:new)
-        .with("body", transaction)
-        .and_return(wrapper)
-
+    it "should wrap the response body in a wrapper" do
       body = listener.call_with_appsignal_monitoring(env)[2]
 
-      expect(body).to be_a(Appsignal::StreamWrapper)
+      expect(body).to be_kind_of(Appsignal::Rack::BodyWrapper)
     end
   end
 end
 
 describe Appsignal::StreamWrapper do
-  let(:stream)      { double }
-  let(:transaction) do
-    Appsignal::Transaction.create(SecureRandom.uuid, Appsignal::Transaction::HTTP_REQUEST, {})
-  end
-  let(:wrapper) { Appsignal::StreamWrapper.new(stream, transaction) }
-
-  describe "#each" do
-    it "calls the original stream" do
-      expect(stream).to receive(:each)
-
-      wrapper.each
-    end
-
-    context "when #each raises an error" do
-      let(:error) { ExampleException }
-
-      it "records the exception" do
-        allow(stream).to receive(:each).and_raise(error)
-
-        expect(transaction).to receive(:set_error).with(error)
-
-        expect { wrapper.send(:each) }.to raise_error(error)
-      end
-    end
-  end
-
-  describe "#close" do
-    it "closes the original stream and completes the transaction" do
-      expect(stream).to receive(:close)
-      expect(Appsignal::Transaction).to receive(:complete_current!)
-
-      wrapper.close
-    end
-
-    context "when #close raises an error" do
-      let(:error) { ExampleException }
-
-      it "records the exception and completes the transaction" do
-        allow(stream).to receive(:close).and_raise(error)
-
-        expect(transaction).to receive(:set_error).with(error)
-        expect(transaction).to receive(:complete)
-
-        expect { wrapper.send(:close) }.to raise_error(error)
-      end
-    end
+  it ".new returns an EnumerableWrapper" do
+    fake_body = double(:each => nil)
+    fake_txn = double
+    stream_wrapper = Appsignal::StreamWrapper.new(fake_body, fake_txn)
+    expect(stream_wrapper).to be_kind_of(Appsignal::Rack::EnumerableBodyWrapper)
   end
 end