Add additional receive error message.

src/Transport.cpp

@@ -312,6 +312,8 @@ void mumlib::Transport::doReceiveSsl() {
 
                     doReceiveSsl();
                 } else {
+                    logger.error("SSL receiver error: %s. Bytes transferred: %d.",
+                                 ec.message().c_str(), bytesTransferred);
                     throwTransportException("receive failed: " + ec.message());
                 }
             });