An `Array` instance referring to another instance via one of its elements.

For example, given:

    value arr = Array({"hello"});
    value context = serialization();
    value refs = context.references(arr);
    assert(is Element elementRef = refs.find((element) => element is Element));
    assert(elementRef.referred(arr) == "hello");
    assert(elementRef.index == 0);

no type hierarchy

- `Element`
  - `ReachableReference`

no subtypes hierarchy

Attributes
`index` | Source Code `shared formal Integer index` The index of the element in the Array which makes the reference.

Inherited Attributes
Attributes inherited from: `Object` `hash`, `string`

Inherited Methods
Methods inherited from: `Object` `equals()`
Methods inherited from: `ReachableReference` `referred()`