Stock futures were flat on Wednesday, as investors kept a wary eye on the Russia-Ukraine situation and looked ahead to key updates on private-sector jobs growth and the health of the services sector.The Federal Reserve’s Beige Book will be released later, and two Federal Reserve officials are scheduled to speak.Dallas Fed President Richard Fisher will speak in Mexico City on the outlook for U.S. and Mexican economies at 7 p.m. Eastern. San Francisco Fed President John Williams is set to talk about Fed operations in Seattle, Wash. at 8:30 p.m. Eastern.