// mspNewReader returns a *Reader that reads from the provided reader.
// The reader will be buffered.
// Return with readMsgpReaderPoolPut when done.
func msgpNewReader(r io.Reader) *msgp.Reader {
	p := readMsgpReaderPool.Get().(*msgp.Reader)
	if p.R == nil {
		p.R = xbufio.NewReaderSize(r, 32<<10)
	} else {
		p.R.Reset(r)
	}
	return p
}