@Override
    public RecordMetadata get() throws InterruptedException, ExecutionException {
        this.result.await();
        if (nextRecordMetadata != null)
            return nextRecordMetadata.get();
        return valueOrError();
    }
The future result of a record send
clients/src/main/java/org/apache/kafka/clients/producer/internals/FutureRecordMetadata.java