Method pingWriterThread

flow/Trace.cpp:571–576

	}

	Future<Void> pingWriterThread() {
		auto ping = new WriterThread::Ping;
		auto f = ping->ack.getFuture();
		writer->post(ping);
		return f;
	}

	void retrieveTraceLogIssues(std::set<std::string>& out) { return issues->retrieveIssues(out); }