public void setValueKey(String valueKey) {
        this.valueKey = valueKey;
    }
<p>
The value that is tracked to produce the metric.
</p>

@param valueKey
       The value that is tracked to produce the metric.
aws-java-sdk-cloudwatchevidently/src/main/java/com/amazonaws/services/cloudwatchevidently/model/MetricDefinition.java