"“There’s no collusion, says the Special Counsel. That takes one sentence. It doesn’t take 200 damn pages. It doesn’t take $35 million dollars,” Levin said, referring to Vol. 2 of the report.
Despite the Democrats warning of a "Saturday Night Massacre" like President Nixon during Watergate, President Trump never asserted executive privilege to prevent documents or people around him from talking to Mueller. He was an open book," Levin argued." Levin
https://www.foxnews.com/politics/mark-levin-on-the-greatest-scandal-in-american-history
I suspect that Mueller will do all he can to avoid giving testimony as it would give some Republicans an interesting opportunity to open a few cans of worms.