presto-main/src/main/java/io/prestosql/operator/index/IndexLoader.java/IndexLoader/streamIndexDataForSingleKey
class IndexLoader:    public IndexedData streamIndexDataForSingleKey(UpdateRequest updateRequest)
    {
        Page indexKeyTuple = updateRequest.getPage().getRegion(0, 1);

        PageBuffer pageBuffer = new PageBuffer(100);
        DriverFactory driverFactory = indexBuildDriverFactoryProvider.createStreaming(pageBuffer, indexKeyTuple);
        Driver driver = driverFactory.createDriver(pipelineContext.addDriverContext());

        PageRecordSet pageRecordSet = new PageRecordSet(keyTypes, indexKeyTuple);
        PlanNodeId planNodeId = driverFactory.getSourceId().get();
        ScheduledSplit split = new ScheduledSplit(0, planNodeId, new Split(INDEX_CONNECTOR_ID, new IndexSplit(pageRecordSet), Lifespan.taskWide()));
        driver.updateSource(new TaskSource(planNodeId, ImmutableSet.of(split), true));

        return new StreamingIndexedData(outputTypes, keyTypes, indexKeyTuple, pageBuffer, driver);
    }