SignalR doesn't echo - xamarin.ios

Question

I'm trying out SignalR.
I started out by making a hub with one method Echo. The hub calls a method "echoed" on the client on connection as well as from the Echo method. The client sees the first call to "echoed" that happens in OnConnected but doesn't see the one from Echo that it calls itself. I suspect the reason is that on the server the hub is instantiated in two different appdomains for both calls.
--- UPDATE: ---
By setting "Maximum Worker Processes" to 1 in IIS Manager (under Application Pools/My app pool/Advanced Settings) the application is forced in a single AppDomain and the callback echo works. Is there a way to make it work with multiple worker processes?
public override System.Threading.Tasks.Task OnConnected()
{
Log.WriteLine("SIGNALR CONNECTED: " + Context.ConnectionId);
Clients.All.Echoed("now connected: "+Context.ConnectionId);
return base.OnConnected();
}
public void Echo(string data)
{
Log.WriteLine("SIGNALR ECHO: " + data);
Clients.All.Echoed(data);
}
The client is .NET (Xamarin for that matter) and it tries to send itself an echo message:
try{
System.Net.ServicePointManager.DefaultConnectionLimit = 10;
HubConnection hubConnect = new HubConnection ("http://localhost:1234/signalr");
hubConnect.Closed+=()=> Console.WriteLine("CLOSED");
hubConnect.Error+=(e)=>Console.WriteLine("ERROR: "+e);
hubConnect.Received+=(s)=>Console.WriteLine("RECEIVED: "+s);
hubConnect.Reconnected+=()=>Console.WriteLine("Reconnected");
IHubProxy ordersHubProxy = hubConnect.CreateHubProxy ("OrdersHub");
ordersHubProxy.On<string> ("Echoed", (echo) =>{
Console.WriteLine ("ECHOED: " + echo );
});
hubConnect.Start().Wait();
Console.WriteLine("CONNECTED: "+hubConnect.Transport.Name);
ordersHubProxy.Invoke("echo", "callback");
} catch (Exception x){
Console.WriteLine ("Unable to connect to SignalR: " + x);
};
On the client side I see an "echoed" event with "now connected: xyzguid" message but I don't see the "callback" message. On the server side there are logged events for both the connection and the echo but the echo doesn't reach the client that asked for it:
Server log:
LOG AppDomain: /LM/W3SVC/2/ROOT/MyApp-11-130157367321605301 Thread: 35
SIGNALR CONNECTED: 8ab4ef99-a41a-4e33-9aba-086a80e2e4a2
LOG AppDomain: /LM/W3SVC/2/ROOT/MyApp-11-130157367360449370 Thread: 1
SIGNALR ECHO: callback
Client log:
CONNECTED: serverSentEvents
ECHOED: now connected: 5cde92f8-9719-4963-b64f-a8bbe39a72ac
RECEIVED: {
"H": "MyHub",
"M": "Echoed",
"A": [
"now connected: 5cde92f8-9719-4963-b64f-a8bbe39a72ac"
]
I expected to see this as well but it doesn't show up:
ECHOED: callback
RECEIVED: ...