code: def pack(mtype, request, rid=None):
      '''pack request to delimited data'''
      envelope = wire.Envelope() 
      if rid is not None:
          envelope.id = rid
      envelope.type = mtype
      envelope.message = request.SerializeToString()
      data = envelope.SerializeToString()
      data = encoder._VarintBytes(len(data)) + data
      return datf pack(mtype, request, rid=None):
      '''pack request to delimited data'''
      envelope = wire.Envelope() 
      if rid is not None:
          envelope.id = rid
      envelope.type = mtype
      envelope.message = request.SerializeToString()
      data = envelope.SerializeToString()
      data = encoder._VarintBytes(len(data)) + data
      return data
docs: pack request to delimited data