Matan Lurey 43599a528a Do not double-increment nextId when using createSurfaceProducer with SurfaceTextures (flutter/engine#50011)
The change is _very_ tiny, but I added some documentation as well.

After this PR, it appears we're "ready" to start using this API once it lands in stable. Hoorah!

Here are local tests using `video_player_android/example`:

## Skia

![Screenshot 2024-01-24 at 10 59 17 AM](https://github.com/flutter/engine/assets/168174/0cc890ee-4c43-47d3-8d3e-4503f5b1a545)

## Impeller

![Screenshot 2024-01-24 at 10 59 46 AM](https://github.com/flutter/engine/assets/168174/bf13a0f0-bcc7-40bf-a521-b61720dab0d9)
2024-01-24 20:15:11 +00:00
Languages
Dart 75%
C++ 16.5%
Objective-C++ 2.9%
Java 2.8%
Objective-C 0.7%
Other 1.9%