ngx_conf_set_keyval_slot  325 src/core/ngx_conf_file.h char *ngx_conf_set_keyval_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
ngx_conf_set_keyval_slot  354 src/http/modules/ngx_http_proxy_module.c       ngx_conf_set_keyval_slot,