startWithStream method
Emits all values and errors in initial
before any values or errors from
this stream.
If this stream is a broadcast stream the result will be as well.
If this stream is a broadcast stream it will miss any events which occur
before initial
closes.
Implementation
Stream<T> startWithStream(Stream<T> initial) {
if (isBroadcast && !initial.isBroadcast) {
initial = initial.asBroadcastStream();
}
return initial.followedBy(this);
}