Function restriction_grant 

pub fn restriction_grant(
    room: &str,
    person: &str,
    until_ms: u64,
    granted_by: Subject,
) -> Grant

The grant that stops person changing anything in room until until_ms (Unix milliseconds, exclusive): undoable changes and outside effects denied on the whole room, reading left alone. It lapses by itself, so a temporary restriction needs nobody to come back and lift it.