Otherwise, HasUnderlyingScalar is false and UnderlyingScalar.IsNone.
// vec[i] = 10, for all i.
UniJaggedD1<int> vec = new(10);
Assert(vec[3] == 10 and vec[42] == 10);
Assert(vec.Get(12) == Some(10));
// underlying constant can be obtained by the optional UnderlyingScalar field.
Assert(vec.HasUnderlyingScalar);
Assert(vec.UnderlyingScalar.IsSome);
Assert(vec.UnderlyingScalar == Some(10));
Assert(vec.UnderlyingScalar.Unwrap() == 10);
public readonly Opt<T> UnderlyingScalar