matchCacheKey method
Returns a Uri that represents the cache key for the given uri.
This can be used to uniquely identify cached media resources.
Implementation
@override
Uri matchCacheKey(Uri uri) {
  Map<String, String> params = {};
  params.addAll(uri.queryParameters);
  params.removeWhere((key, _) => key != 'startRange' && key != 'endRange');
  uri = uri.replace(queryParameters: params.isEmpty ? null : params);
  return uri;
}