How to find out when there are no more results from the Google Datastore data warehouse library

Question

Using the class com.google.cloud.datastore.DatastoreReader.java(v1.3.1) to query Google Cloud Storage, how do I know when there are no more results? I noticed that I continue to return the cursor, even if it seems that there are no results.

Am I guaranteed to get an iterator with values back if there are values ​​left as a result of my query?

Am I guaranteed to get the number of elements set with a limit in the query if there are enough elements in the query result set?

    QueryResults<Entity> queryResults = null;
    do {
        final EntityQuery query = newEntityQueryBuilder()
            .setKind(ENTITY_KIND)
            .setLimit(50)
            .setStartCursor((null!=queryResults)?queryResults.getCursorAfter():Cursor.copyFrom(new byte[0]))
            .build();

        queryResults = datastore.run(query);

        queryResults.forEachRemaining(entity -> {
            // Some operations
        });

    } while ( ??? );