func (tag Tag) IsEmpty() bool {
	return tag.Key == ""
}

// Validate checks this tag.
func (tag Tag) Validate() error {
	if len(tag.Key) == 0 || utf8.RuneCountInString(tag.Key) > 128 {
		return errInvalidTagKey
	}

	if utf8.RuneCountInString(tag.Value) > 256 {
		return errInvalidTagValue
	}

	return nil

	cmd := &cobra.Command{
		Use:   "generate <revision-tag>",
		Short: "Generate configuration for a revision tag to stdout",
		Long: `Create a revision tag and output to the command's stdout. Tag an Istio control plane revision for use with namespace istio.io/rev
injection labels.`,
		Example: `  # Create a revision tag from the "1-8-0" revision
  istioctl tag generate prod --revision 1-8-0 > tag.yaml

  # Apply the tag to cluster

    val request =
      Request.Builder()
        .url("https://square.com")
        .tag(Any::class, tag)
        .build()
    assertThat(request.tag<Any>()).isSameAs(tag)
    assertThat(request.tag(Any::class)).isSameAs(tag)
    assertThat(request.tag(String::class)).isNull()

    // Alternate access APIs also work.
    assertThat(request.tag(Any::class)).isSameAs(tag)
    assertThat(request.tag<Any>()).isSameAs(tag)

    }

    public void test_toString() {
        String tag = "tag", id = "id", css = "css", attrName = "attrName", attrValue = "attrValue";
        PrunedTag prunedtag = new PrunedTag(tag);
        prunedtag.setAttr(attrName, attrValue);
        prunedtag.setId(id);
        prunedtag.setCss(css);
        assertEquals("PrunedTag [tag=" + tag + ", id=" + id + ", css=" + css + ", attrName=" + attrName + ", attrValue=" + attrValue + "]",

        return when {
          peekHeader.tagClass == Adapters.UTC_TIME.tagClass &&
            peekHeader.tag == Adapters.UTC_TIME.tag -> {
            Adapters.UTC_TIME.fromDer(reader)
          }
          peekHeader.tagClass == Adapters.GENERALIZED_TIME.tagClass &&
            peekHeader.tag == Adapters.GENERALIZED_TIME.tag -> {
            Adapters.GENERALIZED_TIME.fromDer(reader)
          }

	exit_1
fi

# "Test if most recent tag update is replicated"
./mc tag set minio2/newbucket "key=val1"
if [ $? -ne 0 ]; then
	echo "expecting tag set to be successful. exiting.."
	exit_1
fi

sleep 10

val=$(./mc tag list minio1/newbucket --json | jq -r .tagset | jq -r .key)
if [ "${val}" != "val1" ]; then
	echo "expected bucket tag to have replicated, exiting..."
	exit_1
fi
# stop minio1

     */
    fun <T : Any> tag(
      type: KClass<T>,
      tag: T?,
    ): Builder = commonTag(type, type.cast(tag))

    /** Attaches [tag] to the request using `Object.class` as a key. */
    open fun tag(tag: Any?): Builder = commonTag(Any::class, tag)

    /**
     * Attaches [tag] to the request using [type] as a key. Tags can be read from a

        private final String tag;

        private final int hash;

        GavCacheKey(String groupId, String artifactId, String version, String tag) {
            this(gav(groupId, artifactId, version), tag);
        }

        GavCacheKey(String gav, String tag) {
            this.gav = gav;
            this.tag = tag;
            this.hash = Objects.hash(gav, tag);
        }

							</Tag>
							<Tag>
								<Key>key2</Key>
								<Value>value2</Value>
							</Tag>
							</And>
						</Filter>`,
			expectedErr: nil,
		},
		{ // Filter with And and multiple Tag tags
			inputXML: ` <Filter>
							<And>
							<Prefix></Prefix>
							<Tag>
								<Key>key1</Key>
								<Value>value1</Value>
							</Tag>
							<Tag>
								<Key>key2</Key>
								<Value>value2</Value>

	exit_1
fi

# "Test if most recent tag update is replicated"
./mc tag set minio2/newbucket "key=val1"
if [ $? -ne 0 ]; then
	echo "expecting tag set to be successful. exiting.."
	exit_1
fi

sleep 10
val=$(./mc tag list minio1/newbucket --json | jq -r .tagset | jq -r .key)
if [ "${val}" != "val1" ]; then
	echo "expected bucket tag to have replicated, exiting..."
	exit_1
fi