presto-main/src/main/java/io/prestosql/spiller/GenericPartitioningSpiller.java/GenericPartitioningSpiller/verifyAllPartitionsRead
class GenericPartitioningSpiller:    @Override
    public synchronized void verifyAllPartitionsRead()
    {
        verify(spilledPartitions.isEmpty(), "Some partitions were spilled but not read: %s", spilledPartitions);
    }