RxCpp is a C++ implementation of the Reactive Extensions library. There are many other languages that have implementations.
The Reactive Extensions can be thought of as an async algorithm and collection library. Instead of using std::iterator pairs RxCpp uses observable as the collection interface and observer as the iterator interface.
Rxcpp is on NuGet! http://www.nuget.org/packages/rxcpp/
An example of a Windows Store Sample app using the rxcpp NuGet package is