Generators don't work

[leshchenko1979]

invl#11

[leshchenko1979]

There is an implementation of this functionality here: invl#16.

However, that implementation restarts the generator on failure. I'm still not sure if this implementation is universal. Restarting the generator will either require the user to implement duplicate removal or, if the decorated generator itself depended on other generators, this might break the sync between the decorated generator and the underlying generator.

Anyway, I'm going to let this issue maroon here until it gets more support / inputs from the community.