nginx 定义的一些状态码

    ngx_string(ngx_http_error_494_page), /* 494, request header too large */
    ngx_string(ngx_http_error_495_page), /* 495, https certificate error */
    ngx_string(ngx_http_error_496_page), /* 496, https no certificate */
    ngx_string(ngx_http_error_497_page), /* 497, http to https */
    ngx_string(ngx_http_error_404_page), /* 498, canceled */
    ngx_null_string, /* 499, client has closed connection */