Come and see how reactive programming is used to build cloud-scale, low-latency, distributed event processing systems at Microsoft, powering end-user experiences such as the personal digital assistant 'Cortana'.In this session we'll show what it took to bring the concepts of Reactive Extensions (Rx) to the cloud to deal with latency, scale, reliability, and other concerns. You'll also learn about the core API abstractions that are used to represent event processing systems of any size across our stack, including the cloud as well as devices and sensors.