class Redis::Connection::Synchrony

def setup_connect_callbacks(conn, f)
  conn.callback do
    @connection = conn
    @state = :connected
    f.resume conn
  end
  conn.errback do
    @connection = conn
    f.resume :refused
  end
  r = Fiber.yield
  raise Errno::ECONNREFUSED if r == :refused
  r
end