public static WebSocketMessage of(final String k1, final Object v1) {
        final Map<String, Object> map = new HashMap<>();
        map.put(k1, v1);
        return new WebSocketMessage(map);
    }
Create a {@link WebSocketMessage} containing a single key/value pair.
stroom-util-shared/src/main/java/stroom/util/shared/WebSocketMessage.java