def encode_string(str)
      str = str.to_s.encode('UTF-8')

      # Force to binary, when assembling the packet
      str.force_encoding('ASCII-8BIT')
      encode_short(str.bytesize) + str
    end
def encode_string(str)
      str = str.to_s.encode('UTF-8')

      # Force to binary, when assembling the packet
      str.force_encoding('ASCII-8BIT')
      encode_short(str.bytesize) + str
    end
Encode a UTF-8 string and return it
 (preceded by the length of the string)