TODO: NOTE: how do Facility

facility.go

@@ -31,6 +31,15 @@ type Facility interface {
 	With(...Field) Facility
 	Enabled(Entry) bool
 	Log(Entry, ...Field) error
+
+	// Log does not call Enabled
+	// Enabled composes like "any"
+
+	// Enabled may be non-deterministic.
+	// Log may drop the entry, but must do so deterministically.
+	// Log must duplicate an deterministic parts of Enabled, otherwise you
+	// won't work correctly under Tee!
+
 }
 
 // WriterFacility creates a facility that writes logs to an io.Writer. By