private static void SubscribeImage(string imageUrl,
IObserver <MemoryStream> observer,
IDictionary <string, string> parameters = null,
IProgress <Tuple <long, long> > progress = null)
{
var subscriptionKey = Guid.NewGuid();
var observable = ReactiveClient.GetImage(imageUrl, parameters, progress);
var disposal = observable.Finally(() => CleanupSubscription(subscriptionKey)).Subscribe(observer);
lock (SyncRoot)
{
CurrentSubscriptions.Add(subscriptionKey, disposal);
}
}
