启用 SO_REUSEADDR 调用 bind() 之前的套接字选项.这允许地址/端口被立即重用，而不是停留在 TIME_WAIT 状态几分钟，等待迟到的数据包到达.

Enable the SO_REUSEADDR socket option before calling bind(). This allows the address/port to be reused immediately instead of it being stuck in the TIME_WAIT state for several minutes, waiting for late packets to arrive.

s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)