When Chicago footwork made the leap from local dance-battle videos to European record labels and worldwide acclaim, DJ Rashad was among its key ambassadors. His 2010 EP Itz Not Rite, for Planet Mu, gave much of the world its first taste of the fast-paced, hyperkinetic sound; on his masterful 2013 Hyperdub album Double Cup, songs like “Show U How” and “She a Go” dug further into the soulful keys and dazzling sample flips that make Rashad’s vision of the genre stand out. Though he died in 2014, posthumous cuts like Afterlife’s “Lost Worlds,” with Traxman, offer a hint of paths not taken; vintage battle tracks like “K Swiss,” meanwhile, are a testament to his peerless programming prowess.