One of Twitch's most popular streamers said on Friday that he was joining a rival streaming platform, Kick, in a significant blow to the Amazon-owned site and a sign of its increasingly strained relationship with content creators.Felix Lengyel, a Canadian known online as xQc, is signing a two-year, roughly $70 million contract, with incentives that could push the total to about $100 million, said his agent, Ryan Morrison.