1. override
Future<String> loadString(String key, { bool cache: true })

Retrieve a string from the asset bundle.

If the cache argument is set to false, then the data will not be cached, and reading the data may bypass the cache. This is useful if the caller is going to be doing its own caching. (It might not be cached if it's set to true either, that depends on the asset bundle implementation.)

Source 

@override
Future<String> loadString(String key, { bool cache: true }) {
  if (cache)
    return _stringCache.putIfAbsent(key, () => _fetchString(key));
  return _fetchString(key);
}