encodeTo method
Convert self to a slice and append it to the destination.
Implementation
@override
void encodeTo(Int8List value, Output output) {
  if (value.length != length) {
    throw Exception(
        'I8ArrayCodec: invalid length, expect $length found ${value.length}');
  }
  for (final val in value) {
    I8Codec.codec.encodeTo(val, output);
  }
}