There is a discrepancy whenTransportExceptionInterface is thrown. Sometimes$e->getDebug() is'' and other times it contains information. Similarly,$transport->getStream()->getDebug(); sometimes returns'' because something else has already beaten you to the call...

This results in you having to do something like the following to get the debug log...

} catch (TransportExceptionInterface $e) {    $log = $e->getDebug() ?: $transport->getStream()->getDebug();

This PR ensures that anyTransportExceptionInterface thrown bysend() sets the debug information. The notable case where this occurs is inhandleAuth which is part ofstart (doHeloCommand).