[racket] Read timeouts on tcp ports?...

I would use "sync/timeout" or "sync/timeout/enable-break", like Sam 
said.  I don't recall using "read-bytes-evt", but I am fond of 
"read-bytes-avail!" in conjunction with "sync/timeout"*.  Would be 
interesting to see how efficiently one could handle a particular I/O 
profile using "read-bytes-avail!", "read-bytes!-evt", and "read-bytes-evt".

Neil V.