It is MUCH faster than trying to feed the message to Postfix
(aka Sendmail) via SMTP/587 because in the case of just piping the
message, Postfix doesn't make me wait until it has done the
DNS lookups it thinks it needs to do in order to process
the message.
I think something is wrong with your setup. I submit over the global
Internet, with extra round trips for authentication and encryption,
and I see submission times in less than a second (you can see more details
here):
https://lists.gnu.org/archive/html/nmh-workers/2015-07/msg00019.html
--Ken
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