writer            502 http/ngx_http_upstream.c     u->output.filter_ctx = &u->writer;
writer            504 http/ngx_http_upstream.c     u->writer.pool = r->pool;
writer           1135 http/ngx_http_upstream.c     u->writer.out = NULL;
writer           1136 http/ngx_http_upstream.c     u->writer.last = &u->writer.out;
writer           1137 http/ngx_http_upstream.c     u->writer.connection = c;
writer           1138 http/ngx_http_upstream.c     u->writer.limit = 0;
writer            260 http/ngx_http_upstream.h     ngx_chain_writer_ctx_t           writer;