Learning RxJava - Second Edition

An example that needs backpressure

When processing each item takes a long time, adding other threads for concurrent processing of the emissions is the way to address the issue. This can be done by adding concurrent operations to an Observable chain using observeOn(), parallelization, and operators such as delay(). With that, the processing becomes asynchronous. This means that multiple parts of the Observable chain can process different emissions at the same time, and the producer can outpace the downstream consumer as they are now operating on different threads.

In asynchronous processing, an emission is no longer, strictly speaking, being handed downstream one at a time from the source all the way to the Observer before starting the next ...