Has anyone explained what information came in midday that allowed outlets to call the Wisconsin Senate race for Ron Johnson?

This race sat without a call for hours and hours, and then without any more ballots coming in at all, was suddenly called for Johnson.

If you look here at the New York Times Key Senate Races plots, there is still a sliver of the bar over the line for Mandela Barnes.

Before the NYT pulled the "Estimated Votes Remaining" there was a suggestion of up to 177,450 votes outstanding.

Barnes would need to win 57.7% of that total to come out ahead in that case. Being that more of the outstanding vote is in republican leaning areas, that seems implausible... except for the fact was that the word out of Wisconsin before the counting, was that it might drag on into Wednesday because mail-in ballots would not be counted until polls closed. If it's in fact mostly mail-in ballots remaining (which heavily favour dems across the country), Barnes getting 57% (even in with Republican leaning areas outstanding) doesn't seem all that far fetched.

I'm not trying to fuel conspiracies with this, I would just like to know how the decided this race was definitely over, because no outlets are explaining. I was hoping for Kornacki to give insight here, but nothing...