[humble] Recording stopped prints only once. (backport #1530) (#1535)

* `Recording stopped` prints only once. (#1530)

Signed-off-by: Tomoya Fujita <Tomoya.Fujita@sony.com>
(cherry picked from commit 73b0772)

# Conflicts:
#	rosbag2_transport/src/rosbag2_transport/recorder.cpp

* Address merge conflicts

Signed-off-by: Michael Orlov <michael.orlov@apex.ai>

---------

Signed-off-by: Michael Orlov <michael.orlov@apex.ai>
Co-authored-by: Tomoya Fujita <Tomoya.Fujita@sony.com>
Co-authored-by: Michael Orlov <michael.orlov@apex.ai>

rosbag2_transport/src/rosbag2_transport/recorder.cpp

@@ -116,9 +116,11 @@ Recorder::~Recorder()
   stop();
 }
 
-
 void Recorder::stop()
 {
+  if (event_publisher_thread_should_exit_) {
+    return;  // We are not in recording and therefore shall not do stop operation.
+  }
   stop_discovery_ = true;
   if (discovery_future_.valid()) {
     auto status = discovery_future_.wait_for(2 * record_options_.topic_polling_interval);
@@ -146,6 +148,7 @@ void Recorder::stop()
 
 void Recorder::record()
 {
+  event_publisher_thread_should_exit_ = false;
   stop_discovery_ = record_options_.is_discovery_disabled;
   paused_ = record_options_.start_paused;
   topic_qos_profile_overrides_ = record_options_.topic_qos_profile_overrides;