Where a custody message has not been received the custody store process will retransmit the message. In the trial
network a retry was attempted after a fixed time if no response had been received. In order to perform a retransmission
the packet was copied from the packet store into the network buffer. As the packet has been in storage the expiry
timestamp was updated using the information in the index to give the new time until expiry. The network buffer with
the updated packet was then transmitted.