Welcome to Checkpoint3 !

This checkpoint is very similar to checkpoint 2, except that packets 
(both data and ack) will be dropped and you will still be expected 
to successfully transfer files. 

Only the debugging levels have changed from checkpoint 2, so for other details,
please see the checkpoint2 README. 

CP3 Debugging Levels:  
The ref_peer supports several debugging levels which you may find
useful.  We cover a few here:
- use '-d 2' if you want to see only control messages. (default)
- use '-d 3' if you just want to see control messages & losses 
- use '-d 7' if you also want to see basic messages plus SEQ number
and ACK number print-outs for each data packet
- use '-d 15' to also see the contents of data structures used to 
handled unreliable data transfer.
- use '-d 63' if you want to see all the debug info fit to print 
(piping it to a file might not be a bad idea).  

Note:  For each of the tests, we have our binary exit directly
after completing the task.  This is not an error.  

