@SuppressWarnings("unchecked")
    public <V> @Nullable V getOrNull(final CloudKey<V> key) {
        return (V) this.map.get(key);
    }
Get the value, or null if not present, without boxing in an optional.

@param key key
@param <V> value type
@return value or null
cloud-core/src/main/java/org/incendo/cloud/key/SimpleMutableCloudKeyContainer.java