presto-main/src/main/java/io/prestosql/operator/exchange/LocalExchangeSink.java/LocalExchangeSink/addPage
class LocalExchangeSink:    public void addPage(Page page)
    {
        requireNonNull(page, "page is null");

        // ignore pages after finished
        // this can happen with limit queries when all of the source (readers) are closed, so sinks
        // can be aborted early
        if (isFinished()) {
            return;
        }

        // there can be a race where finished is set between the check above and here
        // it is expected that the exchanger ignores pages after finish
        exchanger.accept(page);
    }