Function act_many 

pub fn act_many(
    account: &Account,
    password: &str,
    files: &[PathBuf],
    remote: &[(String, ImapOrigin)],
    action: &Action,
) -> Result<(), SyncError>

The same act on several messages of one account, in one connection: a UID set per folder (RFC 9051 §6.4.9). files are kept here; remote are seen on the server only (a search’s), by their folder’s server name. For acts that say nothing of spam (reading, flags, moves, archiving, the trash); the others go one at a time through act, for the spam filter’s logs. The local copies follow as with act. A folder that fails is said (the first problem), the others are still done.