presto-main/src/main/java/io/prestosql/execution/buffer/ClientBuffer.java/ClientBuffer/addPages
class ClientBuffer:    private synchronized void addPages(Collection<SerializedPageReference> pages)
    {
        pages.forEach(SerializedPageReference::addReference);
        this.pages.addAll(pages);

        long rowCount = pages.stream().mapToLong(SerializedPageReference::getPositionCount).sum();
        rowsAdded.addAndGet(rowCount);
        pagesAdded.addAndGet(pages.size());

        long bytesAdded = pages.stream().mapToLong(SerializedPageReference::getRetainedSizeInBytes).sum();
        bufferedBytes.addAndGet(bytesAdded);
    }