Creates a new observable object from the items of that sequence.

// obj.get("item0") = 11
// obj.get("item1") = 22
// obj.get("item2") = 33
// obj.get("item3") = 44
var obj = Enumerable.create(11, 22, 33, 44)
                    .toObservable('(x, index) => "item" + index');