MSG_PEEK          546 http/ngx_http_request.c     n = recv(c->fd, (char *) buf, 1, MSG_PEEK);
MSG_PEEK         2335 http/ngx_http_request.c     n = recv(c->fd, buf, 1, MSG_PEEK);
MSG_PEEK         1000 http/ngx_http_upstream.c     n = recv(c->fd, buf, 1, MSG_PEEK);