docs: public boolean remove(final CacheKey key) {
      Preconditions.checkNotNull(key);
      final EncodedImage encodedImage;
      synchronized (this) {
        encodedImage = mMap.remove(key);
      }
      if (encodedImage == null) {
        return false;
      }
      try {
        return encodedImage.isValid();
      } finally {
        encodedImage.close();
      }
    }