Sorry, i feel that i did't finaly understand..
Check pls my future config:
As far as i understood i need to do following config:
aggregate {
task_id = %{transaction_id}
code = map['test1'] =' '; map['test1'] += event.get('text_message')
map_action = create_or_update
push_map_as_event_on_timeout = true
timeout = 120
timeout_tags = ['aggregated']
}