This shows the information that is logged at each log_level.

warning
 1 Abort
 2 Failsafe mode
notice
 3 Marking host down
   Socket open error
   Too long waiting for child exit
   SMTP response timeout
 4 Non-fatal SMTP response
   Fatal SMTP Response
 5 Single rejected address
info
 6 Compilation times
   Message reading time
   Address reading time
   Batching time
   External spawning time
   Total delivery time
 7 Dest delivery time
 8 Starting
   Batch delivery time
 9 Connection opening time
10 SMTP command turnaround time
11 SMTP Command
12 SMTP Response
