SignalR "Start must be called before data can be sent" when responding to a server request
<p>I have some SignalR client code that invokes a server method after a request from the server:</p>

<pre><code>        var connection = new HubConnection(_hubAddress);
        var hubProxy = _hubConnection.CreateHubProxy(HubName);
        connection.Start().Wait(TimeSpan.FromMinutes(1));
  ...

        hubProxy.On("Client_Method", (string callerId, string requestIdentifier) =&gt;
        {
           if (connection.State == ConnectionState.Connected)
           {
              // error hapening on the invoke call here, despite 
              // the connection state being connected.  
              // Do I need to call Start here?
              hubProxy.Invoke("Proxy_Method_Callback", callerId, requestIdentifier);
           }
        });
</code></pre>

<p>But its throwing an exception: </p>

<blockquote>
  <p>InvalidOperationException: Data cannot be sent because the connection
  is in the disconnected state. Call start before sending any data.</p>
</blockquote>

<p>But if the hubProxy is connected and open to receive the request, why is it erroring on the invoke?</p>