updated readme to address font-subset bug and building with --no-tree…

…-shake-icons to prevent it

example/README.md

@@ -5,32 +5,30 @@ This can be build for any platform.
 
 ```
 
-#build for github>>> flutter build web --release --web-renderer canvaskit --base-href "/material_symbols_icons/"
+#build for github>>>
+```console
+ flutter build web --release --web-renderer canvaskit --base-href "/material_symbols_icons/"
 
 # building for web
 flutter build web --release --web-renderer canvaskit
 
 # serve http to localhost:8080
 dhttpd --path=build\web
-
-
 ```
 
+------
 
-With new tree shaking for web on master channel this still results large savings EVEN WHEN USING EVERY ICON in each of the
-Material Symbols Icons fonts.  (This is most likely because of letters and numbers/regular symbols present in these fonts being removed):
+Building without icon tree shaking - due to a bug in flutter's `font-subset` this is breaking the variable fonts used for Material Symbols Icons.
+See https://github.com/flutter/flutter/issues/125704 .
+I have submitted a PR fixing this in the flutter engine : https://github.com/flutter/engine/pull/41592 .
 
+In the mean time it is necessary to build the web release with the `--no-tree-shake-icons` in order for all variations to work correctly.
+
+```console
+flutter build web --release --web-renderer canvaskit --no-tree-shake-icons --base-href "/material_symbols_icons/"
 ```
-Font asset "CupertinoIcons.ttf" was tree-shaken, reducing it from 283452 to 1236 bytes (99.6% reduction). Tree-shaking
-can be disabled by providing the --no-tree-shake-icons flag when building your app.
-Font asset "MaterialIcons-Regular.otf" was tree-shaken, reducing it from 1645184 to 10808 bytes (99.3% reduction).
-Tree-shaking can be disabled by providing the --no-tree-shake-icons flag when building your app.
-Font asset "MaterialSymbolsOutlined[FILL,GRAD,opsz,wght].ttf" was tree-shaken, reducing it from 6944756 to 4781576 bytes
-(31.1% reduction). Tree-shaking can be disabled by providing the --no-tree-shake-icons flag when building your app.
-Font asset "MaterialSymbolsRounded[FILL,GRAD,opsz,wght].ttf" was tree-shaken, reducing it from 9361824 to 6397020 bytes
-(31.7% reduction). Tree-shaking can be disabled by providing the --no-tree-shake-icons flag when building your app.
-Font asset "MaterialSymbolsSharp[FILL,GRAD,opsz,wght].ttf" was tree-shaken, reducing it from 5848492 to 4079548 bytes
-(30.2% reduction). Tree-shaking can be disabled by providing the --no-tree-shake-icons flag when building your app.
-Compiling lib\main.dart for the Web...                             51.2s
-```
 
+It turns out that the icon tree-shaking is breaking the material symbols variable fonts by dropping the GSUB table.
+This causes rendering errors for some variations (such as Fill->1 Weight->100)  I filed an issue addressing this, https://github.com/flutter/flutter/issues/125704 , as well as a PR fixing font-subset so that it preserves these tables for variable fonts - https://github.com/flutter/engine/pull/41592.
+
+This dropping of the GSUB table was the reason for the 30% saving in font size, even in the case of using every material symbol icon.  Unfortunately we cannot keep having this saving AND have the variable fonts work correctly.  After the `font-subset ` fix from https://github.com/flutter/engine/pull/41592 the size savings when using every icon in the fonts is ~2% instead of ~30%.