{"bob": {"(visit 1 times)": "The message from bob -> processed_by_first_action"}}
{"bob": {"(visit 2 times)": "The message from bob -> processed by second_action"}}
{"john": {"(visit 1 times)": "The message from john -> processed_by_first_action"}}
{"john": {"(visit 2 times)": "The message from john -> processed by second_action"}}
{"john": {"(visit 3 times)": "Second message from john -> processed_by_first_action"}}
{"john": {"(visit 4 times)": "Second message from john -> processed by second_action"}}
{"bob": {"(visit 3 times)": "Second message from bob -> processed_by_first_action"}}
{"bob": {"(visit 4 times)": "Second message from bob -> processed by second_action"}}
{"unknown": {"(visit 1 times)": "Message from unknown -> processed_by_first_action"}}
{"unknown": {"(visit 2 times)": "Message from unknown -> processed by second_action"}}