removeHandler method
Implementation
void removeHandler(String type, ProtocolMessageHandler handler) {
final registeredHandler = _handlers[type];
if (!identical(registeredHandler, handler)) {
throw StateError('handler mismatch for $type');
}
_handlers.remove(type);
final current = _room._protocolInstance.getHandler(type);
if (identical(current, registeredHandler)) {
_room._protocolInstance.removeHandler(type, current!);
}
}