object.</p>
<p>A hash code is a single integer which represents the state of the object
that affects <a href="../../dart-ui/StrutStyle/operator_equals.html">operator ==</a> comparisons.</p>
<p>All objects have hash codes.
The default hash code represents only the identity of the object,
the same way as the default <a href="../../dart-ui/StrutStyle/operator_equals.html">operator ==</a> implementation only considers objects
equal if they are identical (see <a href="../../dart-core/identityHashCode.html">ident