‘Prop bets — wagers on events or nonevents that don’t necessarily affect the outcome of a game — are a rapidly growing segment of the rapidly growing sports gambling industry. And companies are competing to meet the demand, offering an ever-expanding menu of available wagers, ranging from those big-picture, seasonlong bets on individual players such as the Bills’ second-year QB, to granular options offered in-game, including whether a given drive ends in a touchdown or interception.’