code: func (bigEndian) ReadUint16(b io.ByteReader) (uint16, error) {
  	var b1, b2 uint8
  	var err error
  	if b2, err = b.ReadByte(); err != nil {
  		return 0, err
  	}
  	if b1, err = b.ReadByte(); err != nil {
  		return 0, err
  	}
  	return uint16(b1) + uint16(b2)<<8, nil
  }
docs: // ReadUint16 reads a uint16