added async websocket benchmark script.
added async websocket benchmark script.

AJSoft/swoole-src,LinkedDestiny/swoole-src,tutanhamon/swoole-src,swoole/swoole-src,swoole/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,LinkedDestiny/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,LinkedDestiny/swoole-src,AJSoft/swoole-src,swoole/swoole-src,swoole/swoole-src,AJSoft/swoole-src,tutanhamon/swoole-src,AJSoft/swoole-src,tutanhamon/swoole-src,tutanhamon/swoole-src,tutanhamon/swoole-src,tutanhamon/swoole-src,LinkedDestiny/swoole-src,swoole/swoole-src,tutanhamon/swoole-src,AJSoft/swoole-src,LinkedDestiny/swoole-src,AJSoft/swoole-src,AJSoft/swoole-src