Comment 20 for bug 1749475

I realized I should probably get at least most of my current code out there to also help the conversation:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/collab/dbwells/lp1749475_rebase_fixup

working/collab/dbwells/lp1749475_rebase_fixup

The commits there start as basic fixes and get progressively deeper, with the last being the concept of a PreviewEmail reactor (which, as noted, is itself an imperfect solution). Without the last commit, the email does not preview correctly (always sends), but I have the alternative fix for that if I've misunderstood the issues above.