ReactiveX/RxSwift ? reverse-engineered prompt

Build me a Swift library for reactive programming, something like RxSwift, that makes it easy to work with streams of values, UI events, and async work in a clean way.

I want the core part to let me create observables, transform them, combine them, and subscribe to updates. It should also include the iOS and Apple platform helpers for binding to UI, plus small relay types for simple state handling. If it makes sense, include testing support too, so I can write reliable unit tests for reactive code.

Please also add a simple example app or sample code that shows a search screen updating a list as I type, and a few playground style examples so it’s easy to learn. Make it work with Swift Package Manager, and if you need to check current docs or best practices, look them up online.