message: Fix sync benchmarks
diff: @@ -95,6 +95,7 @@ void transform_transactions(TestContext& test_context)
  fixture.start_client(1);
  session_2.wait_for_upload_complete_or_client_stopped();
  session_2.wait_for_download_complete_or_client_stopped();
  + session_2.detach();
  fixture.stop_client(1);
  // Upload changes of first client and wait to integrate changes from second client.
  @@ -175,6 +176,7 @@ void transform_instructions(TestContext& test_context)
  fixture.start_client(1);
  session_2.wait_for_upload_complete_or_client_stopped();
  session_2.wait_for_download_complete_or_client_stopped();
  + session_2.detach();
  fixture.stop_client(1);
  // Upload changes of first client and wait to integrate changes from second client.
  @@ -253,6 +255,7 @@ void connected_objects(TestContext& test_context)
  fixture.start_client(1);
  session_2.wait_for_upload_complete_or_client_stopped();
  session_2.wait_for_download_complete_or_client_stopped();
  + session_2.detach();
  fixture.stop_client(1);
  // Upload changes of first client and wait to integrate changes from second client.
  