\brief An indexing action, to be applied to one or multiple translation units
but not on concurrent threads. If there are threads doing indexing
concurrently, they should use different CXIndexAction objects.
\param CIdx The index object with which the index action will be associated.
\brief An indexing action, to be applied to one or multiple translation units but not on concurrent threads. If there are threads doing indexing concurrently, they should use different CXIndexAction objects.
\param CIdx The index object with which the index action will be associated.