azure-functions-durable-extension: Event raised before ContinueAsNew (w/ preserveUnprocessedEvents: true) is lost in the next execution of the eternal orchestration

Orchestration definition: Eternal orchestration listens for 2 events concurrently. When 1 of them is received, cancel the other one and continue doing some other work and then ContinueAsNew(null, preserveUnprocessedEvents: true)

If an event is raised while its inside the activity func Delay, it is not being received by WaitForExternalEvent in the next execution

`

    [FunctionName(nameof(Delay))]
    public async Task Delay([ActivityTrigger] IDurableActivityContext context, ILogger log, CancellationToken cancellationToken)
    {
        log.LogInformation($"{nameof(EternalOrch)}: {nameof(Delay)}: 20 sec");
        await Task.Delay(TimeSpan.FromSeconds(20));
    }

    [FunctionName(nameof(EternalOrch))]
    public static async Task EternalOrch([OrchestrationTrigger] IDurableOrchestrationContext context, ILogger log)
    {
        log = context.CreateReplaySafeLogger(log);

        using (var cancellationTokenSource = new CancellationTokenSource())
        {
            log.LogInformation($"{nameof(EternalOrch)}: wait for any of event_0 / event_1");
            var winner = await Task.WhenAny(
                context.WaitForExternalEvent("event_0", TimeSpan.FromDays(1), cancellationTokenSource.Token),
                context.WaitForExternalEvent("event_1", TimeSpan.FromDays(1), cancellationTokenSource.Token)
                );

            log.LogInformation($"{nameof(EternalOrch)}: event received, cancel other tasks waiting for event");
            cancellationTokenSource.Cancel();

            //      if winner is event_0, do something
            // else if winner is event_1, do something else
        }

        await context.CallActivityAsync(nameof(Delay), null);

        log.LogInformation($"{nameof(EternalOrch)}: continue as new");
        context.ContinueAsNew(null, preserveUnprocessedEvents: true);
    }

`

Client definition: `

    [FunctionName(nameof(RunEternalOrch))]
    public static async Task<IActionResult> RunEternalOrch(
        [HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequest req,
        [DurableClient] IDurableOrchestrationClient client,
        ILogger log)
    {
        log.LogInformation($"Client: start {nameof(EternalOrch)}");
        var instanceId = await client.StartNewAsync(nameof(EternalOrch));

        var status = await client.GetStatusAsync(instanceId);
        log.LogInformation($"Client: orch status: {status.RuntimeStatus}");

        // wait till its running
        while (status.RuntimeStatus != OrchestrationRuntimeStatus.Running)
        {
            await Task.Delay(TimeSpan.FromMilliseconds(100));
            status = await client.GetStatusAsync(instanceId);
        }

        log.LogInformation($"Client: orch status: {status.RuntimeStatus}");
        log.LogInformation("Client: raise event_0");
        await client.RaiseEventAsync(instanceId, "event_0");

        // delay 10 sec
        await Task.Delay(TimeSpan.FromSeconds(10));

        log.LogInformation("Client: raise event_1");
        await client.RaiseEventAsync(instanceId, "event_1");

        // delay 40 sec
        await Task.Delay(TimeSpan.FromSeconds(40));

        await client.TerminateAsync(instanceId, "just because");

        return new StatusCodeResult((int)HttpStatusCode.OK);
    }

`

Logs:

There is no EternalOrch: event received after Client: raise event_1

[2021-01-30T02:03:46.434Z] Executing ‘RunEternalOrch’ (Reason=‘This function was programmatically called via the host APIs.’, Id=a6bf4b26-9c67-44db-ae68-e42246972876) [2021-01-30T02:03:46.448Z] Client: start EternalOrch [2021-01-30T02:03:47.256Z] Client: orch status: Pending [2021-01-30T02:03:47.334Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=828ac795-7b4c-44a0-aea6-6f0955458967) [2021-01-30T02:03:47.347Z] EternalOrch: wait for any of event_0 / event_1 [2021-01-30T02:03:47.440Z] Executed ‘EternalOrch’ (Succeeded, Id=828ac795-7b4c-44a0-aea6-6f0955458967, Duration=99ms) [2021-01-30T02:03:48.359Z] Client: orch status: Running => [2021-01-30T02:03:48.362Z] Client: raise event_0 [2021-01-30T02:03:49.011Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=d690ce9b-ac5d-4314-84e3-58e24e2d18a6) => [2021-01-30T02:03:49.022Z] EternalOrch: event received, cancel other tasks waiting for event [2021-01-30T02:03:50.341Z] Executed ‘EternalOrch’ (Succeeded, Id=d690ce9b-ac5d-4314-84e3-58e24e2d18a6, Duration=1296ms) [2021-01-30T02:03:51.908Z] Executing ‘Delay’ (Reason=‘(null)’, Id=6b3a5b7f-f525-446e-85fa-109f6ff769ba) [2021-01-30T02:03:51.912Z] EternalOrch: Delay: 20 sec => [2021-01-30T02:03:58.746Z] Client: raise event_1 [2021-01-30T02:03:59.203Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=e2f8bfd1-a57c-477e-b176-a28059daa42a) [2021-01-30T02:03:59.774Z] Executed ‘EternalOrch’ (Succeeded, Id=e2f8bfd1-a57c-477e-b176-a28059daa42a, Duration=570ms) [2021-01-30T02:04:11.929Z] Executed ‘Delay’ (Succeeded, Id=6b3a5b7f-f525-446e-85fa-109f6ff769ba, Duration=20634ms) [2021-01-30T02:04:12.446Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=0d466ea3-696a-4983-80c8-12ec848d58eb) [2021-01-30T02:04:14.278Z] EternalOrch: continue as new [2021-01-30T02:04:14.639Z] Executed ‘EternalOrch’ (Succeeded, Id=0d466ea3-696a-4983-80c8-12ec848d58eb, Duration=2193ms) [2021-01-30T02:04:14.658Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=1bbc4d03-258b-45bf-a629-ebab782e3dc9) [2021-01-30T02:04:14.661Z] EternalOrch: wait for any of event_0 / event_1 [2021-01-30T02:04:14.665Z] Executed ‘EternalOrch’ (Succeeded, Id=1bbc4d03-258b-45bf-a629-ebab782e3dc9, Duration=7ms) [2021-01-30T02:04:39.217Z] 0beb29998e2548a8acf5966aa98ee840: Function ‘EternalOrch (Orchestrator)’ was terminated. Reason: just because. State: Terminated. HubName: TestHubName. AppName: . SlotName: . ExtensionVersion: 2.4.0. SequenceNumber: 25. [2021-01-30T02:04:39.220Z] Executed ‘RunEternalOrch’ (Succeeded, Id=a6bf4b26-9c67-44db-ae68-e42246972876, Duration=52824ms) [2021-01-30T02:04:39.471Z] Executing ‘EternalOrch’ (Reason=‘(null)’, Id=f28fc06c-8e2e-4064-b29c-eee62774db67) [2021-01-30T02:04:39.476Z] Executed ‘EternalOrch’ (Succeeded, Id=f28fc06c-8e2e-4064-b29c-eee62774db67, Duration=5ms)