Implications of the Kotlin coroutines dispatcher initializing only once

I'm working on a project that tries to run several tasks in sandboxes in a Java process. It would be ideal to support Kotlin coroutines inside the sandboxes, but the default dispatcher causes a problem. The first time a coroutine is scheduled on the shared thread pool, the pool threads are started inside the current thread group. If that's triggered by trusted code, the threads belong to a trusted group but can be borrowed by untrusted coroutines. If the creation is triggered by untrusted code, the pool threads are associated with that one job which can be torn down, ruining the pool for any other jobs.

Since the pool is a static member of some internal class, I ended up needing to reload the coroutines library into each untrusted classloader. That way, every copy of the class has its own static members that are initialized inside the sandbox and apply only to one job.