How to check whether the CON and ACK messages are transmitted in the er-rest-example?

[Hardik Rana]

We are trying to run the er-rest-example of contiki in flock lab. We are uploading the er-example-client and er-example-server images on the flock lab.

We have tried running the same examples in cooja and we are getting both CON and ACN message in pcap files.So we want to
know how can we check whether the CON and ACK messages are transmitted in flocklab?

Like where do we need to write the printf statement on the client code when CON is send or when ACK is received?

We wish to calculate RTT using the timestamps of the printf statements.