code: def get_events(subscription_id, watermark)
        req = build_soap! do |type, builder|
          if(type == :header)
          else
            builder.nbuild.GetEvents {
              builder.nbuild.parent.default_namespace = @default_ns
              builder.subscription_id!(subscription_id)
              builder.watermark!(watermark, NS_EWS_MESSAGES)
            }
          end
        end
        do_soap_request(req, response_class: EwsResponse)
      end
docs: Used by pull subscription clients to request notifications from the Client Access server
   @see http://msdn.microsoft.com/en-us/library/aa566199.aspx GetEvents on MSDN
  
   @param [String] subscription_id Subscription identifier
   @param [String] watermark Event bookmark in the events queue