Refer to the examples shown in the Update API description:
http://www.iqengines.com/apidocs/apis/update-api.html
This shows how to handle the case where the Update API times out.

It is not guaranteed that the results for a query will be available before the Update API. Computer vision on the server is typically in less than a second, but human crowdsourcing results can be up to a minute. Hence, if the Update API times out, the recommended behavior is to start another Update API. The other method to get your results back is to use the callback argument in the Query API, where we’ll post the results to URL specified in the callback as soon as the results are available.

We have example code bindings written showing examples:
http://www.iqengines.com/apidocs/code/bindings.html#prebuilt-client-bindings