The name that has been all over the headlines of one of the most closely watched Senate races of the midterms belongs to a man most voters have never heard of. Hasan Piker, the 34-year-old left-wing commentator whose Twitch channel draws millions of viewers, has grown close enough to Michigan Senate nominee Abdul El-Sayed that Republicans now call him El-Sayed's running mate. A national survey of Democratic and Democratic-leaning voters found six in 10 had never heard of him.The Echelon Insights poll, conducted in April, found that Piker remains largely unknown among Democratic voters, underscoring the gap between his enormous...