+/* smtp transport datachunk callback */
+
+#define tc_reap_prev BIT(0) /* Flags: reap previous SMTP cmd responses */
+#define tc_chunk_last BIT(1) /* annotate chunk SMTP cmd as LAST */
+
+struct transport_context;
+typedef int (*tpt_chunk_cmd_cb)(int fd, struct transport_context * tctx,
+ unsigned len, unsigned flags);
+