Because refreshing the inbox is slow and sent messages do not appear immediately in the mailing list archive, I would like to see them in SIT right after sending them.
We could add another type of mail object when sending a message that is ephemeral and destroy it when updating the mailing list. Alternatively, use something similar to TalkMessagePlaceholder
. This probably requires us to think about how different data sources other than SqueakHistory could be combined, if at all.