Calling an Azure Function from SignalR negotiate

Question

I have successfully been able to send my IoT Data to a SignalR Hub and within the Negotiate function I can call a script which will display it on a Brower. Everything is working perfectly. However today I am told that I need to be able to also call an Azure Function from the Negotiate but when I try, and put it above the return I get an error. Can anyone suggest how this can be done? Thanks! Mike

[FunctionName("negotiate")] public static SignalRConnectionInfo GetSignalRInfo( [HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequest req, [SignalRConnectionInfo(HubName = "MyHub")] SignalRConnectionInfo connectionInfo) { return connectionInfo; }