Rules Engine - Inspect the values in a Data Set

Does anyone know how to inspect the values in a Data Set used by a Rules Engine?

I'm testing a function that I have developed in the Rules Engine. This function uses a Data Set.

If I run a test of the function, then at the end I want to be able to see what the final values of the properties (variables) in the Data Set are.

I can see two ways of doing this: (1) use the Details button in the Output section or (2) use Write to Log and output the values of all variables.

But neither of these approaches is working. The data values are not shown.