private RequestFuture<ClientResponse> sendMetadataRequest(MetadataRequest.Builder request) {
        final Node node = client.leastLoadedNode();
        if (node == null)
            return RequestFuture.noBrokersAvailable();
        else
            return client.send(node, request);
    }
Send Metadata Request to the least loaded node in Kafka cluster asynchronously
@return A future that indicates result of sent metadata request
clients/src/main/java/org/apache/kafka/clients/consumer/internals/TopicMetadataFetcher.java