code: public EventSource createEventSource(boolean createAsyncEventSource, String cacheName) {
  
          EventSource eventSource = new DCEventSource(cacheName, createAsyncEventSource);
          if (tc.isDebugEnabled())
              Tr.debug(tc, "Using caller thread context for callback - cacheName= " + cacheName);
  
          return eventSource;
      }
docs: This implements the method in the ServletCacheUnit interface. This method is used to initialize event source for
  invalidation listener
  
  @param createAsyncEventSource
  boolean true - using async thread context for callback; false - using caller thread for callback
  @param cacheName
  The cache name
  @return EventSourceIntf The event source