release method
void
release()
Stops simulating for good: disarms, releases every request waiting out
latency straight to inner (the principal is unchanged, so it is still
the user's request), and passes through from now on, with no delay and no
simulated offline. A request that began before a principalChanged is
not released: it is aborted as the change already decided. If the mode
was offline, online reports the network back, synchronously, so a held
write can drain. Devtools calls this on dispose.
Implementation
void release() {
if (_released) return;
final wasOnline = isOnline;
_released = true;
disarm();
_release.complete();
_change(() => _announce(wasOnline));
}