presto-main/src/main/java/io/prestosql/execution/scheduler/FixedBucketNodeMap.java/FixedBucketNodeMap/getAssignedNode
class FixedBucketNodeMap:    @Override
    public Optional<InternalNode> getAssignedNode(int bucketedId)
    {
        return Optional.of(bucketToNode.get(bucketedId));
    }