The Result<T> returned by Object::invoke_method_synchronously() never holds an error state

[James Henstridge]

Given that Object::invoke_method_synchronously() returns a Result<T> type, I would expect any errors from the method to be reported through result.is_error().

However, it seems invoke_method_synchronously() instead raises std::runtime_error for errors. This is a bit confusing, and I'd expect one of:

 1. errors to be reported via the Result<T> return value.
 2. errors to be reported via exceptions, and invoke_method_synchronously return the result directly rather than using the Result wrapper.