Method sendError

flow/include/flow/IThreadPool.h:134–140

	}

	void sendError(Error const& e) { // Can be called safely from another thread.
		Promise<Void> signal;
		tagAndForwardError(&promiseStream, e, signal.getFuture());
		g_network->onMainThread(std::move(signal),
		                        g_network->isOnMainThread() ? incrementPriorityIfEven(g_network->getCurrentTask())
		                                                    : TaskPriority::DefaultOnMainThread);
	}

private:
	PromiseStream<T> promiseStream;