DeferStream<T> constructor
Constructs a Stream lazily, at the moment of subscription, using
the streamFactory
Implementation
DeferStream(Stream<T> Function() streamFactory, {bool reusable = false})
: _isReusable = reusable,
_factory = reusable
? streamFactory
: (() {
Stream<T>? stream;
return () => stream ??= streamFactory();
}());