#define topt_no_headers 0x020 /* Omit headers */
#define topt_no_body 0x040 /* Omit body */
#define topt_escape_headers 0x080 /* Apply escape check to headers */
+#define topt_use_bdat 0x100 /* prepend chunks with RFC3030 BDAT header */
/* Flags for recipient_block, used in DSN support */