Stop implementing ChunkedConverter.

lib/src/hex/decoder.dart

Index: lib/src/hex/decoder.dart
diff --git a/lib/src/hex/decoder.dart b/lib/src/hex/decoder.dart
index 6a31641fc71afed652f8329b3e6fb2cca8765bae..d7a7555b34c4203314fba296e2755e5ef64c812d 100644
--- a/lib/src/hex/decoder.dart
+++ b/lib/src/hex/decoder.dart
@@ -17,8 +17,7 @@ const hexDecoder = const HexDecoder._();
 /// Because two hexadecimal digits correspond to a single byte, this will throw
 /// a [FormatException] if given an odd-length string. It will also throw a
 /// [FormatException] if given a string containing non-hexadecimal code units.
-class HexDecoder
-    extends ChunkedConverter<String, List<int>, String, List<int>> {
+class HexDecoder extends Converter<String, List<int>> {
   const HexDecoder._();
 
   List<int> convert(String string) {