[C++] Connect timer cancellation does not call timeout callback (apac…

…he#11486)

Master issue: apache#11485

When the PeriodicTask timer is cancelled it calls the handler
which in turn ends up invoking the callback which closes
the socket. This prevents the iteration over multiple endpoints
until the connection succeeds. This change checks the error_code
in the handler and returns if it is operation_cancelled,
avoiding erroneously calling the callback.

Co-authored-by: Jack Vanlightly <[email protected]>

pulsar-client-cpp/lib/PeriodicTask.cc

@@ -43,7 +43,7 @@ void PeriodicTask::stop() {
 }
 
 void PeriodicTask::handleTimeout(const ErrorCode& ec) {
-    if (state_ != Ready) {
+    if (state_ != Ready || ec.value() == boost::system::errc::operation_canceled) {
         return;
     }