Platform and version requirements: JVM (1.3), JS (1.3), Native (1.3)

@ExperimentalStdlibApi fun <E : Element> Element.getPolymorphicElement(
    key: Key<E>
): E?

Returns the current element if it is associated with the given key in a polymorphic manner or null otherwise. This method returns non-null value if either Element.key is equal to the given key or if the key is associated with Element.key via AbstractCoroutineContextKey. See AbstractCoroutineContextKey for the example of usage.