Timeout in connector seems to be dangerously implemented

[drewdzzz]

In all wait methods we firstly check if the timer is not expired and then pass timeout - timer.elapsed() to wait of NetProvider. The wait of NetProvider expects a positive number (or -1 as infinity), but timeout - timer.elapsed() can actually be negative: for example, OS can reschedule the process right after timer.isExpired() call, so it will be actually expired when NetPovider.wait is called.

tntcxx/src/Client/Connector.hpp

Lines 188 to 194 in f9dae01

	while (!conn.hasError() && !conn.futureIsReady(future) &&
	!timer.isExpired()) {
	if (m_NetProvider.wait(timeout - timer.elapsed()) != 0) {
	conn.setError(std::string("Failed to poll: ") +
	strerror(errno), errno);
	return -1;
	}