public void setKey(String key) {
        this.key = key;
    }
<p>
A string that you can use to assign a value. The combination of tag keys and values can help you organize and
categorize your resources.
</p>

@param key
       A string that you can use to assign a value. The combination of tag keys and values can help you organize
       and categorize your resources.
aws-java-sdk-applicationsignals/src/main/java/com/amazonaws/services/applicationsignals/model/Tag.java