pub fn pop_front(&self) -> Option<T>
    where
        T: Eq + Hash,
    {
        let v = self.inner.borrow_mut().pop_front();
        (self.update)();
        v
    }
/// Removes the first element and returns it, or None if the queue is empty.
Removes the first element and returns it, or None if the queue is empty.
Removes the first element and returns it or None if the queue is empty .
pub fn pop_front(&self) -> Option<T>
    where
        T: Eq + Hash,
    {
        let v = self.inner.borrow_mut().pop_front();
        (self.update)();
        v
    }
pub fn pop_front ( & self ) -> Option < T > where T : Eq + Hash , { let v = self . inner . borrow_mut ( ) . pop_front ( ) ; ( self . update ) ( ) ; v }
Removes the first element and returns it, or None if the queue is empty.
Removes the first element and returns it or None if the queue is empty .
&self
&self