Function move_across_from_server 

pub fn move_across_from_server(
    from: &Account,
    from_password: &str,
    source: &str,
    origin: ImapOrigin,
    to: &Account,
    to_password: &str,
    folder: &str,
) -> Result<(), SyncError>

The same for a message seen on its server only (a search’s): read whole from its folder first, its flags with it, then copied and taken off.