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

// readMsgpReaderPoolPut can be used to reuse a *msgp.Reader.
func readMsgpReaderPoolPut(r *msgp.Reader) {
	if r != nil {
		readMsgpReaderPool.Put(r)

	dec := s2DecPool.Get()
	dec.Reset(r)
	mr := msgpNewReader(dec)
	return &metacacheReader{
		mr: mr,
		closer: func() {
			dec.Reset(nil)
			s2DecPool.Put(dec)
			readMsgpReaderPoolPut(mr)
		},
		creator: func() error {
			v, err := mr.ReadByte()
			if err != nil {
				return err
			}
			switch v {
			case 1, 2:
			default: