The Nets have received their best and most realistic trade offer in the Kevin Durant sweepstakes: A prospective deal centered around Boston Celtics’ All-Star guard Jaylen Brown. The Celtics have made an offer for Durant, who requested a trade on June 30, that includes Brown, a one-time All-Star heralded as one of the NBA’s premier two-way wings; sixth man Derrick White; and a draft pick, according to The Athletic. The Nets rejected the Celtics’ offer and asked Boston to include reigning Defensive Player of the Year Marcus Smart, an additional rotation player and draft compensation. As it stand…