Support for custom non-generic class implementing IDictionary<TKey,TValue>

[TheRSP]

Currently, Utf8Json supports serialising to and from classes implementing System.Collections.Generic.IDictionary<,> if and only if that class has two generic type arguments. I ask whether that restriction could be lifted?

Given the class

class MyDictionary: IDictionary<string, object>{
  // ...
}

The following test should pass

// using FluentAssertions
[Test]
public void Can_deserialise_with_Utf8Json()
{
	var Subject = new MyDictionary();
	Subject.Add("a", "alpha");
	Subject.Add("b", 2);
	Subject.Add("c", new object());

	var serialised = Utf8Json.JsonSerializer.Serialize(Subject);
	var deserialised = Utf8Json.JsonSerializer.Deserialize<MyDictionary>(serialised);

	deserialised.Should().BeEquivalentTo(Subject);
}

Currently, I can only achieve this if I also implement System.Collections.IDictionary