More precise description of the kafka timestamp.

Author: sauroter

src/main/java/com/hivemq/extensions/kafka/api/builders/KafkaRecordBuilder.java

@@ -169,7 +169,7 @@ public interface KafkaRecordBuilder {
     /**
      * Set the timestamp of the Kafka record.
      *
-     * @param timestamp the value of the Kafka timestamp.
+     * @param timestamp the value of the Kafka timestamp in milliseconds since UNIX epoch.
      * @return this builder
      * @since 4.4.0
      */

src/main/java/com/hivemq/extensions/kafka/api/model/KafkaRecord.java

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package com.hivemq.extensions.kafka.api.model;
 
 import com.hivemq.extension.sdk.api.annotations.DoNotImplement;
@@ -73,7 +74,7 @@ public interface KafkaRecord {
     @NotNull Optional<byte[]> getValueAsByteArray();
 
     /**
-     * @return an {@link Optional} of the timestamp of this record.
+     * @return an {@link Optional} of the timestamp of this record in milliseconds since UNIX epoch.
      * @since 4.4.0
      */
     @NotNull Optional<Long> getTimestamp();