public bool Equals(OptionUnsafe <T> other) => IsNone && other.IsNone ? true : IsSome && other.IsSome ? EqualityComparer <T> .Default.Equals(Value, other.Value) : false;
public static Arr <OptionUnsafe <B> > Sequence <A, B>(this OptionUnsafe <A> ta, Func <A, Arr <B> > f) => ta.Map(f).Sequence();