code: public boolean isCached(String requestUrl, int maxWidth, int maxHeight, ScaleType scaleType) {
          throwIfNotOnMainThread();
  
          String cacheKey = getCacheKey(requestUrl, maxWidth, maxHeight, scaleType);
          return imageCache.getBitmap(cacheKey) != null;
      }
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.
  @param scaleType  The scaleType of the imageView.
  @return True if the item exists in cache, false otherwise.