Starts a chunked conversion.
The converter works more efficiently if the given sink
is a
ByteConversionSink.
Source
StringConversionSink startChunkedConversion(Sink<List<int>> sink) { if (sink is! ByteConversionSink) { sink = new ByteConversionSink.from(sink); } return new _Utf8EncoderSink(sink); }