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