C# Deep Copy

DeepCopy.cs

public static T? DeepCopy<T>(this T self) where T : class
{
    if (!typeof(T).IsSerializable)
        throw new ArgumentException("Type must be serializable");

    if (ReferenceEquals(self, null))
        return default;

    var formatter = new BinaryFormatter();
    using var stream = new MemoryStream();
    formatter.Serialize(stream, self);
    stream.Seek(0, SeekOrigin.Begin);

    return (T) formatter.Deserialize(stream);
}