Runtime type error when using StreamTransformer-based APIs about rxdart

[hoc081098]

I also had this issue

[Mike278]

See also: dart-lang/web_socket_channel#65, specifically

A recent change in the Dart SDK updated Socket to
implement Stream rather than Stream<List>.
This forwards compatible change calls StreamTransformer.bind()
rather than Stream.transform(), thus putting the stream in a
covariant position and allowing for the transition to Uint8List.

Following this approach, the error goes away if I replace return stream.switchMap<R?>(f); with return SwitchMapStreamTransformer<T?, R?>(f).bind(stream);

[hoc081098]

In mapNotNull and whereNotNull I have already used bind instead of transform. I will update others