code: protected void incrementRequestCount(ResourceType type, int delta) {
      Context c = getContext(type);
      int newRequestCount = c.requestCount + delta;
      c.requestCount = newRequestCount;
      if (newRequestCount > c.maxConcurrentRequestCount) {
        c.maxConcurrentRequestCount = newRequestCount;
      }
    }
docs: Increase a request count for a resource for this session.  It cannot
  exceed the max concurrent request count.
  
  @param type Resource type
  @param delta incremental request count