given this JAVA functional interface, which cannot declare its type parameter T as invariant -

public interface SingleResultCallback<T> {
    /**
     * Called when the operation completes.
     * @param result the result, which may be null.  Always null if e is not null.
     * @param t      the throwable, or null if the operation completed normally
     */
    void onResult(T result, Throwable t);
}

I want to implement this by wrapping a

Continuation<T>

- and I want the type parameter to be in invariant position.

class CallbackImpl<in T>(val cont: Continuation<T>) : SingleResultCallback<T> {
    override fun onResult(result: T, error: Throwable?) {
        if (error != null) {
            cont.resumeWithException(error)
        } else {
            cont.resume(result)
        }
    }
}

However, the

in

produces an error when I try to implement SingleResultCallback

Can I make the compiler trust me?

😂

Btw, SingleResultCallback is from com.mongodb.async.client

Not sure this is the right approach..