code: func (r *Reader) ReadInt32() int32 {
  	if r.err != nil {
  		return 0
  	}
  	var n int
  	n, r.err = io.ReadFull(r.rd, r.b[:4])
  	r.cnt += n
  	if r.err != nil {
  		return 0
  	}
  	return int32(binary.LittleEndian.Uint32(r.b[:4]))
  }
docs: // ReadInt32 reads and returns an int32.