public static <T> List<T> of(T value) {
        return Collections.singletonList(value);
    }
Returns an unmodifiable list containing a single entry.

@param value the List's value.
@param <T> the List's value type.
@return a List containing the specified value.
@throws NullPointerException if the value is {@code null}.
smithy-utils/src/main/java/software/amazon/smithy/utils/ListUtils.java