Optional static class Optional Documentation Code public static bool IsCollectionDefined<T>(IEnumerable<T> collection) public static bool IsCollectionDefined<TKey, TValue>(IDictionary<TKey, TValue> collection) public static bool IsCollectionDefined<TKey, TValue>(IReadOnlyDictionary<TKey, TValue> collection) public static bool IsDefined<T>(T? value) where T : struct public static bool IsDefined(object value) public static bool IsDefined(JsonElement value) public static bool IsDefined(string value)