Do `Signals` in `C#` support arguments of user defined types?

Question

I was trying to define a Signal in C# that takes an instance of a type defined in C# as an argument. I was hoping I'd be able to pass this instance to GDScript.

The code compiles but the Signal does not show up in the editor.
(Using arguments of type string and int for example works fine)

[Signal]
public delegate void SomeSignal(SomeUserDefinedType arg);

I suppose it kind of make sense, given that the GDScript doesn't know about SomeUserDefinedType but still wanted to know if there was any way of passing along this kind of information from C# to GDScript.

Comments

I too would love to know this