code: func (id *ULID) UnmarshalBinary(data []byte) error {
  	if len(data) != len(*id) {
  		return ErrDataSize
  	}
  
  	copy((*id)[:], data)
  	return nil
  }
docs: // UnmarshalBinary implements the encoding.BinaryUnmarshaler interface by
  // copying the passed data and converting it to an ULID. ErrDataSize is
  // returned if the data length is different from ULID length.