DeepCopy.cs

    /// <summary>
    /// Perform a Deep Copy of the object, using Json as a serialization method.
    /// NOTE: Private members are not cloned using this method.
    /// </summary>
    /// <typeparam name="T">The type of object being copied.</typeparam>
    /// <param name="source">The object instance to copy.</param>
    /// <returns>The Deep Copied Object.</returns>
    public static T DeepCopy<T>(this T source)
    {
        if (source is null)
            return default;

        // initialize inner objects individually
        // for example in default constructor some list property initialized with some values,
        // but in 'source' these items are cleaned -
        // without ObjectCreationHandling.Replace default constructor values will be added to result
        var serializeSettings = new JsonSerializerSettings
        {
            FloatParseHandling = FloatParseHandling.Decimal,
            ObjectCreationHandling = ObjectCreationHandling.Replace,
            ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
            TypeNameHandling = TypeNameHandling.All
        };

        var serializer = JsonSerializer.Create(serializeSettings);
        using var stream = new MemoryStream();

        SerializeInto(stream, serializer, source);
        var copy = DeserializeFrom(stream, serializer);

        return copy;

        static void SerializeInto(Stream stream, JsonSerializer serializer, T source)
        {
            using var textWriter = new StreamWriter(stream, leaveOpen: true);
            using var jsonWriter = new JsonTextWriter(textWriter);

            serializer.Serialize(jsonWriter, source);
            jsonWriter.Flush();
            stream.Position = 0;
        }

        static T DeserializeFrom(Stream stream, JsonSerializer serializer)
        {
            using var textReader = new StreamReader(stream);
            using var jsonReader = new JsonTextReader(textReader);

            return serializer.Deserialize<T>(jsonReader);
        }
    }