Im just starting out with coroutines, so this may be a weird question. Is it possible and how would I go about implementing a

MainCoroutineDispatcher

that simply runs the coroutines on an existing main thread?

you can convert an Executor to a dispatcher. https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-core/kotlinx.coroutine[…]/java.util.concurrent.-executor/as-coroutine-dispatcher.html

I think what you're looking for is

runBlocking

which creates a dispatcher on the calling thread for the coroutines to run. If you're looking to create a dispatcher object, I think that can be done in a useful way since the dispatcher has to take control of the thread by blocking it.

Turned out the underlying program already chose to have their own

Executor

for running things on the main thread, so I could just do as @Chrimaeon suggested and delegate to this. Even though it seems a bit hacky using this "InternalCoroutinesApi" to set

Dispatchers.Main

myself everything is working fine so far. Thank you all for helping out!