How to Issue Delete Requests in Elasticsearch Using PyFlink's ElasticsearchSink

Question

I'm working with PyFlink and trying to perform delete operations on my Elasticsearch index using the built-in ElasticsearchSink class. I've successfully used this sink for adding new documents and updating existing ones in Elasticsearch, but I'm struggling to understand how to structure my input data to execute a delete request.

Below is the relevant section of my Flink job:

def main(config: ElasticsearchExampleConfig) -> None:
    """Sink an example message into Elasticsearch and delete it."""
    env = StreamExecutionEnvironment.get_execution_environment()

    # Add JARs to the classpath
    jars = [path.absolute().as_uri() for path in Path("./jars").glob("*.jar")]
    env.add_jars(*jars)

    # Set up the Elasticsearch sink
    elasticsearch_sink = (
        Elasticsearch7SinkBuilder()
        .set_bulk_flush_max_actions(1)
        .set_emitter(ElasticsearchEmitter.static_index("test-index", "id"))
        .set_hosts([config["elasticsearch_endpoint"]])
        .set_connection_username(config["elasticsearch_username"])
        .set_connection_password(config["elasticsearch_password"])
        .build()
    )
    
    # Set up a sequence messages to trigger the delete action.
    stream = [
        # This message creates the document
        {
            "id": "example-message",
            "hello": "world"
        },
        # This message should delete the document
        {
            "id": "example-message",
            # What should the message body look like?
        }
    ]

    env.from_collection(stream, Types.MAP(Types.STRING(), Types.STRING())).sink_to(
        elasticsearch_sink,
    ).name(
        "Elasticsearch Sink",
    )

    env.execute("Elasticsearch Example")

I understand that the ElasticsearchSink can handle different types of requests, but I am not sure how to format the second message in the stream to trigger a delete operation for the document with the ID example-message.

Is there a specific structure or flag that needs to be set in the message to indicate a delete operation? Any insights or examples on how to achieve this would be greatly appreciated.