castFrom<S, T> method Null safety

Stream<T> castFrom <S, T>(
  1. Stream<S> source

Adapts source to be a Stream<T>.

This allows source to be used at the new type, but at run-time it must satisfy the requirements of both the new type and its original type.

Data events created by the source stream must also be instances of T.


static Stream<T> castFrom<S, T>(Stream<S> source) =>
    new CastStream<S, T>(source);