flatMap<R> abstract method
Returns a stream consisting of the results of replacing each element of this stream with the contents of a mapped stream produced by applying the provided mapping function to each element.
Example
final words = GenericStream.of(['hello world', 'foo bar'])
.flatMap((s) => GenericStream.of(s.split(' ')));
Implementation
GenericStream<R> flatMap<R>(GenericStream<R> Function(T) mapper);