public void addAll(Map<? extends String, ? extends List<String>> values) {
        for (Entry<? extends String, ? extends List<String>> entry : values.entrySet()) {
            add(entry.getKey(), entry.getValue());
        }
    }
Adds all the entries of the given map to this. This is the same as calling {@link #add(String, List)} for each
entry in <code>values</code>.

@param values the values to be added to this.
jdisc_core/src/main/java/com/yahoo/jdisc/HeaderFields.java