What is an empty interface used for

Question

I am looking at nServiceBus and came over this interface

namespace NServiceBus
{
    public interface IMessage
    {
    }
}

What is the us

Answer 1

I'd say its used for "future" reference or if you want to share some objects, meaning you could have 10 classes each implementing this interface.

And have them sent to a function for work on them, but if the interface is empty, I'd say its just "pre"-work.