redis_connection_for_subscriptions

# File actioncable/lib/action_cable/subscription_adapter/evented_redis.rb, line 49
        def redis_connection_for_subscriptions
          ensure_reactor_running
          @redis_connection_for_subscriptions || @server.mutex.synchronize do
            @redis_connection_for_subscriptions ||= self.class.em_redis_connector.call(@server.config.cable).tap do |redis|
              redis.on(:reconnect_failed) do
                @logger.error "[ActionCable] Redis reconnect failed."
              end

              redis.on(:failed) do
                @logger.error "[ActionCable] Redis connection has failed."
              end
            end
          end
        end