code: public void marshall(GetDownloadUrlForLayerRequest getDownloadUrlForLayerRequest, ProtocolMarshaller protocolMarshaller) {
  
          if (getDownloadUrlForLayerRequest == null) {
              throw new SdkClientException("Invalid argument passed to marshall(...)");
          }
  
          try {
              protocolMarshaller.marshall(getDownloadUrlForLayerRequest.getRegistryId(), REGISTRYID_BINDING);
              protocolMarshaller.marshall(getDownloadUrlForLayerRequest.getRepositoryName(), REPOSITORYNAME_BINDING);
              protocolMarshaller.marshall(getDownloadUrlForLayerRequest.getLayerDigest(), LAYERDIGEST_BINDING);
          } catch (Exception e) {
              throw new SdkClientException("Unable to marshall request to JSON: " + e.getMessage(), e);
          }
      }
docs: Marshall the given parameter object.