UnloadedIndexKeyRecordSet unloadedKeysRecordSet = new UnloadedIndexKeyRecordSet(indexSnapshotReference.get(), indexTypes, requests);
// Drive index lookup to produce the output (landing in indexSnapshotBuilder)
Driver driver = driverFactory.createDriver(pipelineContext.addDriverContext());
PlanNodeId sourcePlanNodeId = Iterables.getOnlyElement(driverFactory.getSourceIds());
driver.updateSource(new TaskSource(sourcePlanNodeId, ImmutableSet.of(new ScheduledSplit(0, new Split("index", new IndexSplit(unloadedKeysRecordSet)))), true));
while (!driver.isFinished()) {
ListenableFuture<?> process = driver.process();
checkState(process.isDone(), "Driver should never block");
}