/**
  * Create a {@code CodecHttpMessageConverter} with the given {@link Decoder}.
  *
  * @param decoder the decoder to use
  */
 public DecoderHttpMessageReader(Decoder<T> decoder) {
   this.decoder = decoder;
   this.readableMediaTypes =
       (decoder != null
           ? MediaType.asMediaTypes(decoder.getDecodableMimeTypes())
           : Collections.emptyList());
 }