ReactiveX/RxJava ? reverse-engineered prompt

I want to build a Java library to help with asynchronous and event-based programming, kind of like Reactive Extensions but for the JVM. The main idea is to get away from all the low-level threading, synchronization, and thread-safety headaches.

It should let me create "observable sequences" which are basically streams of data or events. Then, I want to be able to chain a bunch of operators onto these streams to transform, filter, or combine them declaratively. It needs to support different kinds of flows: one that can handle a lot of data without getting overwhelmed (backpressure is important), another for simpler streams, one for when you expect exactly one item, and another for when you just need to know if an operation finished or failed.

Make sure it's built for modern Java and uses virtual threads to handle concurrency efficiently. The core library shouldn't require any third-party dependencies at runtime. The goal is a clean, fluent API for composing async operations.