Feature request: show message size in Emacs

[Jorge P. de Morais Neto]

Hi.  My mail account is provided by Disroot.  It is a non-profit
pay-as-you-wish provider of Internet services respecting free/libre
software ethics.  The mailbox is limited to 1GB, so I move unnecessary
messages from the IMAP server to a local subdirectory of my maildir that
is seen by Notmuch.  I like to know the message size when I decide to
move it out of the IMAP server, so I invoke
`notmuch-show-view-raw-message' and see the raw message size in the
Emacs modeline.  This is a bit time consuming, so I humbly request
Notmuch to:

1. Provide the option to show message size on notmuch-search,
   notmuch-show and presumably also on notmuch-tree.
2. For accuracy, compute the total size of all message duplicate files.
3. Perhaps also show the number of duplicate files.

This would be even more important if the "notmuch purge" proposal is
implemented, which, by the way, I support.

And thank you for this great tool!  Is there a mechanism to donate to
Notmuch?

Regards
-- 
- <https://jorgemorais.gitlab.io/justice-for-rms/>
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