St?phane MERLE:
> even if the 1s pause looks like pleasing hotmail, this will not
> be usable for the amount of email we send (multi million a day).
> Is there other ways to drop the rate delivery for a specific
> transport ?
I suppose you overlooked this text in the documentation:
To enable the delay, specify a non-zero time value (an integral value
plus an optional one-letter suffix that specifies the time unit).
Time units: s (seconds), m (minutes), h (hours), d (days), w (weeks).
The default time unit is s (seconds).
This answers your question about less-than-one second delays.
Wietse