Avoid an unnecessary allocation in recvMessage
Avoid an unnecessary allocation in recvMessage

Creating a readBuf here is a bit of an overkill since it's only used to
read the length of the message.  Invoke encoding/binary directly to
avoid the allocation, resulting in a ~10% performance gain in a
benchmark as described in #270.

everalbum/pq,StabbyCutyou/pq,dongzerun/pq,henrylee2cn/pq,VividCortex/pq,bugreplaydev/pq,cbandy/go-pq,ympons/pq,stvp/pq,lib/pq,calebthompson/pq,jnewmano/pq,bugreplaydev/pq,johto/pq,amaniak/pq,beni55/pq,ScriptRock/pq,jnewmano/pq,sammi/pq,ympons/pq,springning/pq,erichnascimento/pq,flynn/pq