ngx_output_chain  151 core/ngx_buf.h ngx_int_t ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in);
ngx_output_chain  141 http/ngx_http_copy_filter_module.c         rc = ngx_output_chain(ctx, in);
ngx_output_chain 1347 http/ngx_http_upstream.c     rc = ngx_output_chain(&u->output, u->request_sent ? NULL : u->request_bufs);