All the Streams generated by the previous recipes need to be subscribed in order to emit data Streams. This kind of data Stream is called the cold stream. Many of the real-time applications nowadays need services that emit a data Stream continuously once the server starts even without any subscription. Thus, data emission in this recipe is not bounded by any subscribers which gives each subscriber a different set of Streams every now and then within such a period. This recipe will discuss snippets that implement synchronous and non-blocking Stream operations.