EDIT: I also got it to work by including an additional default (parameterless) constructor.

I had a lot of issues with this one trying to use a constructor to initialize the name property.

i.e, I had to remove:
public PersonEventArgs(string name)
{
Name = name;
}

And pass the name by doing:

ContactNotify?.Invoke(this, new PersonEventArgs(){Name=name});

Any attempt to pass name resulted in a CS7036 error depicting there was no parameter 'name' of 'PersonEventArgs.PersonEventArgs(string)'