private StringBuilder combineVals(StringBuilder currValue, List<String> values) {
    for (String value : values) {
      if (currValue.length() > 0) {
        currValue.append(MULTIPLE_HEADER_VALUE_DELIMITER);
      }
      currValue.append(value);
    }
    return currValue;
  }
Combines {@code values} into {@code currValue} by creating a comma separated string.
@param currValue the value to which {@code values} have to be appended to.
@param values the values that need to be appended to @code currValue}.
@return the updated @code currValue}.
ambry-rest/src/main/java/com/github/ambry/rest/NettyRequest.java