code: public boolean isCached(String requestUrl, int maxWidth, int maxHeight) {
          return isCached(requestUrl, maxWidth, maxHeight, ScaleType.CENTER_INSIDE);
      }
docs: Checks if the item is available in the cache.
  @param requestUrl The url of the remote image
  @param maxWidth The maximum width of the returned image.
  @param maxHeight The maximum height of the returned image.
  @return True if the item exists in cache, false otherwise.