We tried to get ‘Avengers’ directors the Russo Brothers — in Park City this week — to spill spoilers about ‘Infinity War’

The Slamdance Film Festival has often been thought of as Sundance’s bratty little brother, having been founded in 1995 by a group of guys whose films had been rejected from the older, bigger, better-known fest.Twenty-three years in, Slamdance has grown up, become respectable, and can boast of some major success stories. Christopher Nolan’s first film, “Following,” debuted at the fest; he went on to direct little, barely seen, shoestring-budget indies like “The Dark