> Also, the async/await approach, such as Kotlin coroutines, has its own problems. Even though it aims to model the one task per thread approach, it can’t rely on any native JVM construct. For example, Kotlin coroutines based the whole story on suspending functions, i.e., functions that can suspend a coroutine. However, the suspension is wholly based upon non-blocking IO, which we can achieve using libraries based on Netty, but not every task can be expressed in terms of non-blocking IO. Ultimately, we must divide our program into two parts: one based on non-blocking IO (suspending functions) and one that does not. This is a challenging task; it takes work to do it correctly. Moreover, we lose again the simplicity we want in our programs.
> The above are reasons why the JVM community is looking for a better way to write concurrent programs. Project Loom is one of the attempts to solve the problem. So, let’s introduce the first brick of the project: virtual threads.