description

# 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`.

## Implementation

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