message: Fix deadlock in connection_handler
diff: @@ -465,10 +465,21 @@ void ConnectionHandlerImpl::OnSessionStartedCallback(
  return;
  }
  #endif // ENABLE_SECURITY
  +
  + auto find_connection =
  + [this](const transport_manager::ConnectionUID& primary_connection_handle)
  + -> Connection* {
  sync_primitives::AutoReadLock lock(connection_list_lock_);
  - ConnectionList::iterator it =
  - connection_list_.find(primary_connection_handle);
  - if (connection_list_.end() == it) {
  + auto it = connection_list_.find(primary_connection_handle);
  + if (it != connection_list_.end()) {
  + return it->second;
  + }
  + return nullptr;
  + };
  +
  + Connection* connection = find_connection(primary_connection_handle);
  +
  + if (!connection) {
  SDL_LOG_ERROR("Unknown connection!");
  protocol_handler_->NotifySessionStarted(
  context,
  @@ -477,7 +488,6 @@ void ConnectionHandlerImpl::OnSessionStartedCallback(
  return;
  }
  - Connection* connection = it->second;
  context.is_new_service_ =
  !connection->SessionServiceExists(session_id, service_type);
  