pub fn empty() -> Ref<'arena, T> {
        Ref {
            ptr: AtomicPtr::new(0 as *mut T),
            _lifetime: PhantomData,
        }
    }
/// Create a new empty `Ref`. Dereferencing this reference before it is set
/// will panic. The reference may be set exactly once.
Create a new empty `Ref`. Dereferencing this reference before it is set
will panic. The reference may be set exactly once.
Create a new empty ` Ref ` . Dereferencing this reference before it is set will panic . The reference may be set exactly once .
pub fn empty() -> Ref<'arena, T> {
        Ref {
            ptr: AtomicPtr::new(0 as *mut T),
            _lifetime: PhantomData,
        }
    }
pub fn empty ( ) -> Ref < ' arena , T > { Ref { ptr : AtomicPtr :: new ( 0 as * mut T ) , _lifetime : PhantomData , } }
Create a new empty `Ref`.
Create a new empty ` Ref ` .