Return type of decodeUtf16AsIterable and variants. The Iterable type provides an iterator on demand and the iterator will only translate bytes as requested by the user of the iterator. (Note: results are not cached.)

class IterableUtf16Decoder implements Iterable<int> {
  final _CodeUnitsProvider codeunitsProvider;
  final int replacementCodepoint;

  IterableUtf16Decoder._(this.codeunitsProvider, this.replacementCodepoint);

  Utf16CodeUnitDecoder iterator() =>
      new Utf16CodeUnitDecoder.fromListRangeIterator(codeunitsProvider(),
          replacementCodepoint);
}