Get the markup context which has been cached. This might be useful
to retrieve the markup which was returned performBlockingInteraction
calls in order to save an additional getMarkup call.
The cached markup context or null in case the cache is empty.
Update the cache which holds the markup context. This might be useful
to store the markup which was returned by performBlockingInteraction
calls in order to save an additional getMarkup call.
Updateing the cache with a null value clears the markup cache.
Parameters: markupContext - The markup context or null in case the cache should be cleared.