SelectMany working with large objects

This => http://stackoverflow.com/questions/38601057/reactive-extensions-selectmany-with-large-objects

void Main()
{
var selectMany = Enumerable.Range(1, 100)
.Select(i => new LargeObject(i))
.ToObservable()
.Select(o => Observable.FromAsync(() => DoSomethingAsync(o)))
.Merge(4);

// var selectMany = Enumerable.Range(1, 100)
// .ToObservable()
// .Select(i => Observable.Defer(() => Observable.Return(new LargeObject(i)))
// .SelectMany(o => Observable.FromAsync(() => DoSomethingAsync(o)))
// ).Merge(4);

selectMany.Subscribe(o => Console.WriteLine(o.Id));
}