close method
void
close()
Implementation
void close() {
if (_canceled) return;
_canceled = true;
if (!hasListener) {
_dispose();
return;
}
final active = List.of(activeUnits, growable: false);
final paused = List.of(pausedUnits, growable: false);
final dirty = List.of(dirtyUnits, growable: false);
active.forEach(_close);
paused.forEach(_close);
dirty.forEach(_close);
}