What If Bill Clinton Had Stonewalled Impeachment?

This is neither here nor there, but back when Republicans were impeaching Bill Clinton I always wondered what would happen if Clinton simply refused to participate and Democrats boycotted everything except the final Senate vote. Until now, it was just an idle counterfactual, like wondering what would have happened if Germany had invented the atomic bomb first.
But this is apparently going to be Trump’s strategy. The details of the underlying offenses are very different, of course, but it looks like I’m finally going to get at least an idea of whether stonewalling is a good strategy in an impeachment case.