Generating Flowable with backpressure at source

So far, we have learned to use standard libraries that handle backpressure at the downstream. However, is this optimal? Is it always desirable to cache and drop emissions whenever the downstream can't keep up? The answer to both questions is simply NO. Instead, the better policy would be to backpressure the source at the first place.

Flowable.generate() serves the exact same purpose. It's somewhat similar to Flowable.create(), but with a little difference. Let's take a look at an example, and then we will try to understand how it works and what are the differences between Flowable.create() and Flowable.generate().

Note

Note that use Flowable.fromIterable() as it respects backpressure. So, consider using Flowable.fromIterable() whenever you can convert your source to an Iterator. Use Flowable.generate() only where you need something more specific, as it is way more complex.

Consider the following code:

    fun main(args: Array<String>) { 
...