public static <V> CIHashMap<V> empty() {
        //noinspection unchecked
        return (CIHashMap<V>) EMPTY;
    }
A standard {@link HashMap} keyed with case-insensitive {@link CIKey} keys.
<p>
Various methods of {@link HashMap} are overridden so you can interact with the
map using {@link String} or {@link CIKey} keys, with {@link String} keys getting
converted to {@link CIKey} on the fly.
</p>
stroom-util-shared/src/main/java/stroom/util/shared/string/CIHashMap.java