初始化swoole，设置回调
swoole_server.c
PHP_METHOD(swoole_server, on)
服务端发送数据给客户端
PHP_METHOD(swoole_server, send)
send流程
swoole_server.send->swServer_tcp_send->[factory->finish]->swFactoryProcess_finish->swWorker_send2reactor->swSocket_write_blocking/write pipe
reactor监听事件->swReactorThread_onPipeReceive->swReactorThread_send->swConnection_send/set epoll out