text: class TCP:
      """
      TCP层对象
      protocol是本层协议名称
      """
      def __init__(self, src, dst, stream, length, seq, ack, time_delta, time_relative, protocol):
          self.src = src
          self.dst = dst
          self.length = length
          self.stream = stream
          self.seq = seq
          self.ack = ack
          self.time_delta = time_delta
          self.time_relative = time_relative
          self.protocol = protocol
  
      def __repr__(self):
          return '<%s Layer>' % self.protocol.upper()