1. the known users of async don't upgrade
2. async becomes a win when concurrent connections exceed a few hundred simultaneous
3. anyone that needs async should be looking at Haraka instead
4. the perl async dependencies aren't maintained
The patch below fixes many errors of the form:
*** WARNING: line containing nothing but whitespace in paragraph at line 37 in file writing.pod
*** WARNING: line containing nothing but whitespace in paragraph at line 40 in file writing.pod
There are also a couple of minor typo-fixes.