getNextPlatformViewId method Null safety
Allocates a unique identifier for a platform view.
A platform view identifier can refer to a platform view that was never created, a platform view that was disposed, or a platform view that is alive.
Typically a platform view identifier is passed to a platform view widget which creates the platform view and manages its lifecycle.
Implementation
int getNextPlatformViewId() => _nextPlatformViewId++;