ngx_free_chain    152 core/ngx_output_chain.c                         ngx_free_chain(ctx->pool, cl);
ngx_free_chain    325 event/ngx_event_pipe.c                 ngx_free_chain(p->pool, ln);
ngx_free_chain    818 event/ngx_event_pipe.c         ngx_free_chain(p->pool, cl);
ngx_free_chain    284 http/ngx_http_write_filter_module.c         ngx_free_chain(r->pool, ln);