public void setClientRequestToken(String clientRequestToken) {
        this.clientRequestToken = clientRequestToken;
    }
<p>
A unique identifier for this <code>CancelUpdateStack</code> request. Specify this token if you plan to retry
requests so that CloudFormation knows that you're not attempting to cancel an update on a stack with the same
name. You might retry <code>CancelUpdateStack</code> requests to ensure that CloudFormation successfully received
them.
</p>

@param clientRequestToken
       A unique identifier for this <code>CancelUpdateStack</code> request. Specify this token if you plan to
       retry requests so that CloudFormation knows that you're not attempting to cancel an update on a stack with
       the same name. You might retry <code>CancelUpdateStack</code> requests to ensure that CloudFormation
       successfully received them.
aws-java-sdk-cloudformation/src/main/java/com/amazonaws/services/cloudformation/model/CancelUpdateStackRequest.java