Function ruma_state_res::event_auth::check_event_sender_in_room

pub fn check_event_sender_in_room<E, F>(
    sender: &UserId, 
    fetch_state: F
) -> Option<bool> where
    E: Event,
    F: Fn(&EventType, &str) -> Option<Arc<E>>, 

Is the event’s sender in the room that they sent the event to.