pub fn key(&self) -> K {
        match self {
            Entry::Occupied(entry) => entry.kd.into(),
            Entry::Vacant(entry) => entry.kd.into(),
        }
    }
/// Returns this entry's key.
///
/// # Examples
///
/// ```
/// # use slotmap::*;
/// let mut sm = SlotMap::new();
/// let mut sec: SparseSecondaryMap<_, ()> = SparseSecondaryMap::new();
///
/// let k = sm.insert(1);
/// let entry = sec.entry(k).unwrap();
/// assert_eq!(entry.key(), k);
/// ```
Returns this entry's key.
Returns this entry ' s key .
pub fn key(&self) -> K {
        match self {
            Entry::Occupied(entry) => entry.kd.into(),
            Entry::Vacant(entry) => entry.kd.into(),
        }
    }
pub fn key ( & self ) -> K { match self { Entry :: Occupied ( entry ) => entry . kd . into ( ) , Entry :: Vacant ( entry ) => entry . kd . into ( ) , } }
Returns this entry's key.
Returns this entry ' s key .
&self
examples
None
use slotmap::*;
let mut sm = SlotMap::new();
let mut sec: SparseSecondaryMap<_, ()> = SparseSecondaryMap::new().

let k = sm.insert(1);
let entry = sec.entry(k).unwrap();
assert_eq!(entry.key(), k);
```
let mut sm = SlotMap :: new () ; let mut sec : SparseSecondaryMap<_ () > = SparseSecondaryMap :: new () . let k = sm . insert ( 1 ) ; let entry = sec . entry ( k ) . unwrap () ; assert_eq! ( entry . key () k ) ; ` ` `