public static QueryTemplate append(
      QueryTemplate queryTemplate,
      Iterable<String> values,
      CollectionFormat collectionFormat,
      boolean decodeSlash) {
    List<String> queryValues = new ArrayList<>(queryTemplate.getValues());
    queryValues.addAll(
        StreamSupport.stream(values.spliterator(), false)
            .filter(Util::isNotBlank)
            .collect(Collectors.toList()));
    return create(
        queryTemplate.getName(),
        queryValues,
        StandardCharsets.UTF_8,
        collectionFormat,
        decodeSlash);
  }
Append a value to the Query Template.

@param queryTemplate to append to.
@param values to append.
@return a new QueryTemplate with value appended.
core/src/main/java/feign/template/QueryTemplate.java