docs: public BaseServerResponseException addResponseHeader(String theName, String theValue) {
  		Validate.notBlank(theName, "theName must not be null or empty");
  		Validate.notBlank(theValue, "theValue must not be null or empty");
  		if (getResponseHeaders().containsKey(theName) == false) {
  			getResponseHeaders().put(theName, new ArrayList<>());
  		}
  		getResponseHeaders().get(theName).add(theValue);
  		return this;
  	}