round-trip latency is similar to one-way latency

[hanghoo]

Hi @ChuanyuXue,

I got similar results when testing udp_rrt and udp_latency. It seems like division 2 of udp_rrt.py needs to be removed in the following function.

def listen(self, buffer_size: int, verbose: bool, save: Optional[str], q: Queue)-> None:
        latency = 0.0
        while True:
            msg, _ = self._udp_socket.recvfrom(buffer_size)
            recv_time = time.time_ns()
            packet_index = int.from_bytes(msg[:4], 'big')
            send_time = int.from_bytes(msg[4:12], 'big')
            old_latency = latency
            latency = round(((recv_time - send_time) * 1e-9) / 2, 6)
            jitter = abs(latency - old_latency)
            recv_size = len(msg)