public static <V> Map<String, V> convertToStringMap(final Map<CIKey, ? extends V> map) {
        return NullSafe.map(map)
                .entrySet()
                .stream()
                .collect(Collectors.toMap(
                        entry -> entry.getKey().get(),
                        Entry::getValue));
    }
Convert a {@link String} keyed map into a {@link CIKey} keyed map.
Accepts null keys, but not null values, and never returns a null.
stroom-util-shared/src/main/java/stroom/util/shared/string/CIKey.java