“Bob has just sent me a message telling me he’d like to send me a keepalive. Send him acknowledgement. Start timer. Read the keepalive from the network. Timer is still running. Figure out that need to send Arya a propagated keepalive. Send arya a message saying I’d like to send him a keepalive. Arya replies with acknowledgement. Stop timer and add elapsed time to the keepalive sent to Arya."