* Fix for nan pressure values and values outside min and max pressure ranges

* media query check

* Added sample to AnimatedWidget

* Updated AnimatedWidget example to use listenable from parent

* Made progress private and changed widget name

Fix issue where SliverPersistentHeader that is both floating and pinned would scroll down when scrolling past the beginning of the ScrollView (#27433)

* Add outer try block for obtainKey errors. Add docs.

* change to // from ///, and do specific error handling

* Add return statement after error

* Add test

* Roll engine to f45572e95f93edb89b6750a4f36ad8ed7c0a2560

* update goldens

* update goldens version

* Fixes Cupertino switch vibration

* Added sample code for a simple Icon, ref: #21136

* Removed duplicate line.

* Fixed incoreect parameter.

* Update icon.dart

Removed empty prose and added better context for sample code. Changed sample code for better visibility in execution of default app themes.

* Alas, Trailing space.

Nixed trailing space in comments.

Fixes https://github.com/flutter/flutter/issues/25025

Re-applies #27409 by reverting #27919

The analyzer issue (dart-lang/sdk#35940) has been temporarily
worked around by virtue of #27929

This converts all remaining "## Sample code" segments into snippets, and fixes
the snippet generator to handle multiple snippets in the same dartdoc block
properly.

I also generated, compiled, and ran each of the existing application samples,
and fixed them up to be more useful and/or just run without errors.

This PR fixes these problems with examples:

1. Switching tabs in a snippet now works if there is more than one snippet in
   a single dartdoc block.
2. Generation of snippet code now works if there is more than one snippet.
3. Contrast of text and links in the code sample block has been improved to
   recommended levels.
4. Added five new snippet templates, including a "freeform" template to make
   it possible to show examples that need to change the app instantiation.
5. Fixed several examples to run properly, a couple by adding the "Scaffold"
   widget to the template, a couple by just fixing their code.
6. Fixed visual look of some of the samples when they run by placing many
   samples inside of a Scaffold.
7. In order to make it easier to run locally, changed the sample analyzer to
   remove the contents of the supplied temp directory before running, since
   having files that hang around is problematic (only a problem when running
   locally with the `--temp` argument).
8. Added a `SampleCheckerException` class, and handle sample checking
   exceptions more gracefully.
9. Deprecated the old "## Sample code" designation, and added enforcement for
   the deprecation.
10. Removed unnecessary `new` from templates (although they never appeared in
   the samples thanks to dartfmt, but still).

Fixes #26398
Fixes #27411

This makes the code more consistent but also fixes our flutter-analyze bot.

Issue https://github.com/dart-lang/sdk/issues/35940

This reverts commit 46cabdab.

This reverts commit d8cd2ff4.

This reverts commit 1d93e924.

In particular, make debugVisitOnstageChildren only work in debug mode, and add documentation.

* Fixes offset and unblocks roll

This makes Android raw key event handling use the "character" data coming from the engine properly, and gets rid of the "toLowerCase" hack that I was using to normalize logical key events, in favor of using the new "plainCodePoint" that has the unmodified code point (the code point as if no modifier keys were pressed).

just a small typo 
the word "the constraints" is duplicated