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