code: func (rh *RefHasher) Hash(data []byte) []byte {
  	// if data is shorter than the base length (maxDataLength), we provide padding with zeros
  	d := make([]byte, rh.maxDataLength)
  	length := len(data)
  	if length > rh.maxDataLength {
  		length = rh.maxDataLength
  	}
  	copy(d, data[:length])
  	return rh.hash(d, rh.maxDataLength)
  }
docs: // Hash returns the BMT hash of the byte slice
  // implements the SwarmHash interface