private void Subscribe(IUserActor userActor)
{
Log.Info($"{_user.Login}");
if (_syncSubscription != null)
{
throw new InvalidOperationException("Already subscribed to changes.");
}
var start = new ChangeSummary();
start.Add(userId: _user.UserId);
// Changes streamed from the queue
_syncSubscription = _syncManager.Changes
.ObserveOn(TaskPoolScheduler.Default)
.StartWith(start) // Run an initial sync no matter what.
.Select(c =>
Observable.FromAsync(() => _syncContext.Sync(c))
.Catch <Unit, Exception>(LogError <Unit>))
.Concat() // Force sequential evaluation
.Subscribe();
// Polling for updates
_pollSubscription = _PollInterval
.ObserveOn(TaskPoolScheduler.Default)
.StartWith(0)
.Select(_ =>
Observable.FromAsync(() => userActor.Sync())
.Catch <Unit, Exception>(LogError <Unit>))
.Concat() // Force sequential evaluation
.Subscribe();
}