Your app can request the content of a Screen to be invalidated by calling the
Screen.invalidate method. The host subsequently calls back into your
app's Screen.onGetTemplate method to retrieve the template with the new
contents.
When refreshing a Screen, it's important to understand the specific content
in the template that can be updated so the host doesn't count the new template
against the template quota. To learn more, see Template restrictions.
We recommend that you structure your screens to have a one-to-one mapping
between a Screen and the type of template it returns through its
onGetTemplate implementation.