Reduce sending of unnecessary acks
- Reduce sending of unnecessary acks. (#267)
$ go version
go version go1.4.2 linux/amd64
xtaci/smux@60c611f
xtaci/kcp-go@ffaad6e
xtaci/kcptun@229a4a8
$ go version
go version go1.4.2 linux/amd64
xtaci/smux@60c611f
xtaci/kcp-go@ffaad6e
xtaci/kcptun@229a4a8