Function ruma_state_res::event_auth::get_named_level

pub fn get_named_level<E, F>(fetch_state: F, name: &str, default: i64) -> i64 where
    E: Event,
    F: Fn(&EventType, &str) -> Option<Arc<E>>, 

Helper function to fetch a field, name, from a “m.room.power_level” event’s content. or return default if no power level event is found or zero if no field matches name.