extern void transport_update_waiting(host_item *, uschar *);
extern BOOL transport_write_block(int, uschar *, int);
extern BOOL transport_write_string(int, const char *, ...);
+extern BOOL transport_headers_send(address_item *, int, uschar *, uschar *,
+ BOOL (*)(int, uschar *, int, BOOL), BOOL, rewrite_rule *, int);
extern BOOL transport_write_message(address_item *, int, int, int, uschar *,
uschar *, uschar *, uschar *, rewrite_rule *, int);
extern void tree_add_duplicate(uschar *, address_item *);