Generate C# properties in Interfaces using SWIG

I want to generate a C# interface using SWIG 3.0.12. For public functions this works as expected. However if I try to add properties to the interface they are not part of the generated interface.

Is it possible to tell SWIG to add properties to the public interface?

Here is a minimal example:

My C++ class looks like:

class IA
{
  public:
    virtual std::string GetX() = 0;
    virtual void SetX(const std::string& x) = 0;

    virtual void MyFunction() = 0;
};

Using the following interface file:

%module example

%{
#include "IA.h"
%}

%include <std_string.i>
%include <attribute.i>
%include <swiginterface.i>

%attribute(IA, std::string, X, GetX, SetX);
%interface(IA);

%include "IA.h"

The generated IA.cs looks like:

public virtual void MyFunction() {
    examplePINVOKE.IA_MyFunction(swigCPtr);
}

public string X {
    set {
        examplePINVOKE.IA_X_set(swigCPtr, value);
        if (examplePINVOKE.SWIGPendingException.Pending) throw examplePINVOKE.SWIGPendingException.Retrieve();
    }
    get {
        string ret = examplePINVOKE.IA_X_get(swigCPtr);
        if (examplePINVOKE.SWIGPendingException.Pending) throw examplePINVOKE.SWIGPendingException.Retrieve();
        return ret;
    } 
}

The generated IASwigInterface.cs looks like:

public interface IASwigInterface {
    [System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]
    global::System.Runtime.InteropServices.HandleRef GetInterfaceCPtr();
    void MyFunction();
}

What I would expect SWIG to generate for the IASwigInterface.cs is something like:

public interface IASwigInterface {
    [System.ComponentModel.EditorBrowsable(System.ComponentModel.EditorBrowsableState.Never)]
    global::System.Runtime.InteropServices.HandleRef GetInterfaceCPtr();
    void MyFunction();
    string X { get; set; } //<- I want the property to be part of the interface
}

Does anyone know how this can be achieved?