presto-main/src/main/java/io/prestosql/operator/HashBuilderOperator.java/HashBuilderOperator/finishSpilledInput
class HashBuilderOperator:    private void finishSpilledInput()
    {
        checkState(state == State.SPILLING_INPUT);
        if (!spillInProgress.isDone()) {
            // Not ready to handle finish() yet
            return;
        }
        checkSuccess(spillInProgress, "spilling failed");
        state = State.INPUT_SPILLED;
    }