public void setKey(String key) {
        this.key = key;
    }
<p>
A unique identifier for the tag. Maximum length: 128 characters. Valid characters: Unicode letters, digits, white
space, _ . / = + - % @
</p>

@param key
       A unique identifier for the tag. Maximum length: 128 characters. Valid characters: Unicode letters,
       digits, white space, _ . / = + - % @
aws-java-sdk-kinesis/src/main/java/com/amazonaws/services/kinesis/model/Tag.java