equal are allowed to have the same hash code,
it is even technically allowed that all instances have the same hash code,
but if clashes happen too often, it may reduce the efficiency of hash-based
data structures like <code>HashSet</code> or <code>HashMap</code>.</p>
<p>If a subclass overrides <a href="flutter_page_video/FadeAnimation/hashCode.html">hashCode</a>, it should override the
<a href="flutter_page_video/FadeAnimation/operator_equals.html">operator ==</a> operator as well to maintain consistency.</