default <V> void set(final @NonNull String key, final @Nullable V value) {
        if (value == null) {
            this.remove(key);
        } else {
            this.store(key, value);
        }
    }
Sets the {@code value} associated with the given {@code key}.
<p>
If the {@code value} is {@code null} the {@code key} will be {@link #remove(String) removed}.

@param <V>   the type of the value
@param key   the key
@param value the value
cloud-core/src/main/java/org/incendo/cloud/key/MutableCloudKeyContainer.java