startWith method
Emits initial
before any values or errors from the this stream.
If this stream is a broadcast stream the result will be as well.
If this stream is a broadcast stream, the returned stream will only
contain events of this stream that are emitted after the initial
value
has been emitted on the returned stream.
Implementation
Stream<T> startWith(T initial) =>
startWithStream(Future.value(initial).asStream());