public String getKey() {
        return this.key;
    }
<p>
Part of the key:value pair that defines a tag. You can use a tag key to describe a category of information, such
as "customer." Tag keys are case-sensitive.
</p>

@return Part of the key:value pair that defines a tag. You can use a tag key to describe a category of
        information, such as "customer." Tag keys are case-sensitive.
aws-java-sdk-fms/src/main/java/com/amazonaws/services/fms/model/Tag.java