1.配置默认server外，只有一个xquic站点时，nginx -t 检查一切正常，如下

server { 
        listen          443  reuseport http2 ssl default_server;
        listen          443  reuseport xquic default_server;
        ssl_certificate /usr/local/nginx/conf/ssl/nginx.crt;
        ssl_certificate_key /usr/local/nginx/conf/ssl/nginx.key;
	server_name     _;
        #root            /usr/local/nginx/html/;
	return          444;
}

  server { 
        listen          443  xquic;
        listen          443  http2 ssl;
	server_name     a.test.com;
       ...
}

1. 配置两个以上xquic站点时，nginx -t 检查，会报：nginx: [warn] protocol options redefined for 0.0.0.0:443 in /usr/local/nginx/conf/vhost/aaa.conf:79,
   warn信息里的79行，内容就是第二个server 的
   listen 443 xquic;

server { 
        listen          443  reuseport http2 ssl default_server;
        listen          443  reuseport xquic default_server;
        ssl_certificate /usr/local/nginx/conf/ssl/nginx.crt;
        ssl_certificate_key /usr/local/nginx/conf/ssl/nginx.key;
	server_name     _;
	return          444;
}

  server { 
        listen          443  xquic;
        listen          443  http2 ssl;
	server_name     a.aaa.com;
       ...
}

  server { 
        listen          443  xquic;
        listen          443  http2 ssl;
	server_name     b.bbb.com;
       ...
}