private static void addKey(final CIKey ciKey) {
        // Add it to our static maps, so we can get a common CIKey either from its
        // exact case or its lower case form.
        KEY_TO_COMMON_CIKEY_MAP.put(ciKey.get(), ciKey);
        LOWER_KEY_TO_COMMON_CIKEY_MAP.put(ciKey.getAsLowerCase(), ciKey);
    }
Add key to the map of common keys for re-use.
<p>
Only intended for use on static and commonly used {@link CIKey} instances due to the cost of
string interning and storage.
</p>
stroom-util-shared/src/main/java/stroom/util/shared/string/CIKeys.java