Reactive Streams

Reactive Streams are all about processing an asynchronous stream of data items, where applications react to data items as they receive them. This model is more memory-efficient, as it doesn't rely on any in-memory data.

Reactive Streams have four main components:

1. Publisher.
2. Subscriber.
3. Subscription.
4. Processor.

The Publisher publishes a stream of data, to which the Subscriber is asynchronously subscribed. The Processor transforms the data stream without the need for changing the Publisher or the Subscriber. The Processor (or multiple Processors) sits between the Publisher and the Subscriber to transform one stream of data to another.