Use future for kafka return

Author: graduta

src/alice/dip/kafka/KafkaProducerInterface.java

@@ -49,9 +49,9 @@ public KafkaProducerInterface(String bootstrapServers, String topic, Serializer<
      * @param key - message key for partitioning
      * @param value - message value (payload)
      */
-    public void send(K key, V value) {
+    public java.util.concurrent.Future<org.apache.kafka.clients.producer.RecordMetadata> send(K key, V value) {
         ProducerRecord<K, V> record = new ProducerRecord<>(topic, key, value);
-        producer.send(record);
+        return producer.send(record);
     }
 
     /**