Store and retrieve Lucene documents in a specific order

I'm using Lucene 7.3.1. In order to allow early termination in my custom collector, I'm trying to have documents stored in a specific order at indexing time. The goal is to have them returned in that order in the collect method of my collector

I have added a field for sorting in all my documents

doc.add(new SortedDocValuesField("mySort", new BytesRef(value)));

My indexWriter is defined as

IndexWriterConfig conf = new IndexWriterConfig(analyzer);
conf.setIndexSort(new Sort(new SortField("mySort", SortField.Type.STRING)));
indexWriter = new IndexWriter(directory, conf);

Then when searching

indexReader.search(query, myCollector);

I'm expecting, in the accept method of myCollector, to receive the matching documents in the mySort order, but they are still ordered by docId

I have seen samples to do that in older versions of Lucene, and I tried to translate that to Lucene 7, but still not working

What am I doing wrong ? Thanks