anchor.diff:  
     cursor = collection.createCursor(where.sortBy('a').skip(300).limit(10));
   
  -  await cursor.stream.forEach((e) => counter++);
  +  counter = await cursor.stream.length;
     expect(counter, 10);
     expect(cursor.state, State.CLOSED);
     expect(cursor.cursorId, 0);
  
positive.code: 
    int count = 0;
    int sum = 0;
    await collection.remove();
    await collection.insertAll([
      {"name": "Vadim", "score": 4},
      {"name": "Daniil", "score": 4},
      {"name": "Nick", "score": 5}
    ]);
  
    await collection.find().forEach((v1) {
      count++;
      sum += v1["score"];
    });
  
    expect(count, 3);
    expect(sum, 13);
  
negative.code: 
    int count = 0;
    Cursor cursor = new Cursor(db, collection, where.limit(10));
    count = await cursor.stream.length;
    expect(count, 0);
  
    await insertManyDocuments(collection, 1000);
  
    cursor = new Cursor(db, collection, null);
    count = await cursor.stream.length;
  
    expect(count, 1000);
    expect(cursor.cursorId, 0);
  