+ BOOL af_tcp_fastopen_conn:1; /* delivery connection used TCP Fast Open */
+ BOOL af_tcp_fastopen:1; /* delivery usefully used TCP Fast Open */
+ BOOL af_tcp_fastopen_data:1; /* delivery sent SMTP commands on TCP Fast Open */
+ BOOL af_pipelining:1; /* delivery used (traditional) pipelining */
+#ifdef SUPPORT_PIPE_CONNECT
+ BOOL af_early_pipe:1; /* delivery used connect-time pipelining */
+#endif