pub fn front_mut(&mut self) -> Option<&mut A::Item> {
        if !self.is_empty() {
            Some(&mut self[0])
        } else {
            None
        }
    }
/// Provides a mutable reference to the front element, or `None` if the
/// sequence is empty.
///
/// # Examples
///
/// ```
/// use arraydeque::ArrayDeque;
///
/// let mut buf: ArrayDeque<[_; 2]> = ArrayDeque::new();
/// assert_eq!(buf.front_mut(), None);
///
/// buf.push_back(1);
/// buf.push_back(2);
///
/// assert_eq!(buf.front_mut(), Some(&mut 1));
/// ```
Provides a mutable reference to the front element, or `None` if the
sequence is empty.
Provides a mutable reference to the front element or ` None ` if the sequence is empty .
pub fn front_mut(&mut self) -> Option<&mut A::Item> {
        if !self.is_empty() {
            Some(&mut self[0])
        } else {
            None
        }
    }
pub fn front_mut ( & mut self ) -> Option < & mut A :: Item > { if ! self . is_empty ( ) { Some ( & mut self [ 0 ] ) } else { None } }
Provides a mutable reference to the front element, or `None` if the
sequence is empty.
Provides a mutable reference to the front element or ` None ` if the sequence is empty .
&mut self
examples
```
use arraydeque::ArrayDeque.

let mut buf: ArrayDeque<[_; 2]> = ArrayDeque::new();
assert_eq!(buf.front_mut(), None).




` ` ` use arraydeque :: ArrayDeque . let mut buf : ArrayDeque< [ _ ; 2 ] > = ArrayDeque :: new () ; assert_eq! ( buf . front_mut () None ) .