Hello, I'm struggling with timeouts when using flo...

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[Xabier Gorostidi]

Hello, I'm struggling with timeouts when using flow. Consider the following snippet:

override fun startScan(
    timeout: Long
): Flow<Result<List<Devices>>> {
    return merge(
        devicesData.foundList.map { Result.Success(it) },
        flow {
            delay(timeout)
            emit(Result.Error(Errors.DeviceDiscoveryError))
        }
    )
        .onStart {
            // Here device discovery is launched, but it's callback based so withTimeout doesn't fit very well here
        }
        .map {
            logger().d("device received here")
            stopScan()
            it
        }
        .catch { e ->
            logger().e("Error: $e")
            stopScan()
            emit(Result.Error(Errors.DeviceDiscoveryError))
        }
        .flowOn(ioDispatcher)
}

What I want is the first item emitted by either of those two flows may finish the returning one and ignore future ones. For example, in this example, if a device is found, the timeout will also be called there emitting another item. I've tried using withTimeout and also coroutineContext.cancelChildren() when an item is received, but I'm getting into a loop when that's captured in the catch block. What should be the best approach for this problem?