yield???

public IEnumerable<int> A()
{
    for (int i = 0; i <= 10; i += 2)
        yield return i;
}



public IEnumerable<int> B()
{
    var ints = new List<int>();
    for (int i = 0; i <= 10; i += 2) 
        ints.Add(i);

    return ints;
}