@Override
        protected boolean isFull() {
            return (requests.size() >= config.getMaxBatchSize()) || (batchSizeBytes >= config.getMaxBatchSizeBytes());
        }
Processes the batch once closed. Is <em>NOT</em> called with a lock on {@code this}.
However, it's passed a local copy of both the {@code requests} and {@code futures} lists
made while holding the lock.
aws-java-sdk-sqs/src/main/java/com/amazonaws/services/sqs/buffered/SendQueueBuffer.java