When updating packages, do not delete the simulated SDK directory until all pub invocations have finished (#112975)

Enables pinch-to-zoom in InteractiveViewer on web via PointerScaleEvent.

Export `elapseBlocking` to test binding, so slow sync work can be simulated such as a slow widget build (#112619)

* Adding snackbar theme data width field

* Whitespace formatting

* Update docstrings

* version update

* tidy up

* Revert auto text formatting

* Text formatting

* Remove whitespace

* Test tidy

* Whitespace fix

* y Please enter the commit message for your changes. Lines starting

* whitespace

* test fixes

* de-British-ification

* comment modification

https://github.com/flutter/engine/compare/37d8342ccac159892d93008f64c9a3ac0ed2f9e1...cef721963336c56e88127d82db6400ff1d247b26

* Revert "[Windows] Move to Visual Studio 2019" (https://github.com/flutter/engine/pull/36606)

Issue: https://github.com/flutter/flutter/issues/112894

Allows the creation of virtual in-app keyboards written in Flutter.  Especially useful for embedded environments.