Unfortunately I can't reproduce it in the test app. But I've discovered the bug with
gocode (https://github.com/nsf/gocode). Here's what happens, if you run standalone
'gocode' command all it does is using "net/rpc" package:
1. connect to the server (or run it and connect if it's not running already)
2. disconnect

So.. basically it's `client, err := rpc.Dial(...)` and then `client.Close()`. But
sometimes the net/rpc package prints this nasty log message, here's how it looks like:


[nsf @ gocode]$ gocode
[nsf @ gocode]$ gocode
[nsf @ gocode]$ gocode
2012/02/23 14:33:55 rpc: client protocol error: use of closed network connection
[nsf @ gocode]$ gocode
2012/02/23 14:33:55 rpc: client protocol error: use of closed network connection
[nsf @ gocode]$ gocode
[nsf @ gocode]$ gocode


I did 'hg bisect' on this, the bug appears after this commit:
http://code.google.com/p/go/source/detail?r=a5b623616453

Probably some kind of desync in logic between new "net" principles and the
"net/rpc".

So.. the bug appeared in a5b623616453 commit, between weekly.2012-02-07 and
weekly.2012-02-14.