http_connection   304 http/ngx_http_request.c     r->http_connection = hc;
http_connection  1209 http/ngx_http_request.c     hc = r->http_connection;
http_connection  2407 http/ngx_http_request.c     hc = r->http_connection;
http_connection   421 http/ngx_http_request.h     ngx_http_connection_t            *http_connection;