code: func (ftp *FTP) ReadAndDiscard() (int, error) {
  	var i int
  	bufferSize := ftp.reader.Buffered()
  	for i = 0; i < bufferSize; i++ {
  		if _, err := ftp.reader.ReadByte(); err != nil {
  			return i, err
  		}
  	}
  	return i, nil
  }
docs: // ReadAndDiscard reads all the buffered bytes and returns the number of bytes
  // that cleared from the buffer