pub enum Presence {
Present,
Absent,
Unknowable(Unreadable),
}Expand description
Whether a key is in a Surface.
Variants§
Present
Absent
Unknowable(Unreadable)
The surface cannot answer for this key: withhold rather than treat it as absent.
Trait Implementations§
impl Copy for Presence
impl Eq for Presence
impl StructuralPartialEq for Presence
Auto Trait Implementations§
impl Forget for Presence
impl Freeze for Presence
impl Move for Presence
impl RefUnwindSafe for Presence
impl Send for Presence
impl Sync for Presence
impl Unpin for Presence
impl UnsafeUnpin for Presence
impl UnwindSafe for Presence
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more