I am trying to integrate Flink with Elasticsearch 2.1.1, I am using the maven dependency 

```
     <dependency>
        <groupId>org.apache.flink</groupId>
        <artifactId>flink-connector-elasticsearch2_2.10</artifactId>
        <version>1.1-SNAPSHOT</version>
    </dependency>

```

and here's the Java Code where I am reading the events from a Kafka queue (which works fine) but somehow the events are not getting posted in the Elasticsearch and there is no error either, in the below code if I change any of the settings related to port, hostname, cluster name or index name of ElasticSearch then immediately I see an error but currently it doesn't show any error nor any new documents get created in ElasticSearch

```
       StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

    // parse user parameters
    ParameterTool parameterTool = ParameterTool.fromArgs(args);

    DataStream<String> messageStream = env.addSource(new FlinkKafkaConsumer082<>(parameterTool.getRequired("topic"), new SimpleStringSchema(), parameterTool.getProperties()));

    messageStream.print();

    Map<String, String> config = new HashMap<>();
    config.put(ElasticsearchSink.CONFIG_KEY_BULK_FLUSH_MAX_ACTIONS, "1");
    config.put(ElasticsearchSink.CONFIG_KEY_BULK_FLUSH_INTERVAL_MS, "1");

    config.put("cluster.name", "FlinkDemo");

    List<InetSocketAddress> transports = new ArrayList<>();
    transports.add(new InetSocketAddress(InetAddress.getByName("localhost"), 9300));

    messageStream.addSink(new ElasticsearchSink<String>(config, transports, new TestElasticsearchSinkFunction()));

    env.execute();
}
private static class TestElasticsearchSinkFunction implements ElasticsearchSinkFunction<String> {
    private static final long serialVersionUID = 1L;

    public IndexRequest createIndexRequest(String element) {
        Map<String, Object> json = new HashMap<>();
        json.put("data", element);

        return Requests.indexRequest()
                .index("flink").id("hash"+element).source(json);
    }

    @Override
    public void process(String element, RuntimeContext ctx, RequestIndexer indexer) {
        indexer.add(createIndexRequest(element));
    }
}

```