For anyone wondering what CEP is... (from the blog) "in contrast to traditional DBMSs where a query is executed on stored data, CEP executes data on a stored query."
And
"Apache Flink with its true streaming nature and its capabilities for low latency as well as high throughput stream processing is a natural fit for CEP workloads."
Anyone looking at generic low latency, high throughput systems can look at Disruptor by LMAX [0]. Spring's Reactor framework supports it out-of-the-box.