in lib/fake_async.dart [149:157]
void elapseBlocking(Duration duration) {
if (duration.inMicroseconds < 0) {
throw ArgumentError('Cannot call elapse with negative duration');
}
_elapsed += duration;
var elapsingTo = _elapsingTo;
if (elapsingTo != null && _elapsed > elapsingTo) _elapsingTo = _elapsed;
}