Add additional quality of service channel modes to NetworkManager

I need to add a few additional quality of service channel modes to NetworkManager and I'm attempting to do it in this way:

Code (CSharp):

1.  NetworkManager netMan;
2.  
3.     void Start () {
4.     ConnectionConfig cc = new ConnectionConfig();
5.  
6.     reliableChannel = cc.AddChannel(QosType.Reliable);
7.     reliableSeqChannel = cc.AddChannel(QosType.ReliableSequenced);
8.     reliableFragChannel = cc.AddChannel(QosType.ReliableFragmented);
9.     unreliableChannel = cc.AddChannel(QosType.Unreliable);
10.     unreliableSeqChannel = cc.AddChannel(QosType.UnreliableSequenced);
11.     cc.PacketSize = 1440;
12.  
13.     netMan.connectionConfig = cc;
14.     }

But I'm getting the error : `Property or indexer 'NetworkManager.connectionConfig' cannot be assigned to -- it is readonly`

If the property is read-only then what is the proper way to create additional channels to NetworkManager?

...full function below

Code (CSharp):

1. using System.Collections;
2.     using System.Collections.Generic;
3.     using UnityEngine;
4.     using UnityEngine.Networking;
5.  
6.     public class Server : MonoBehaviour {
7.  
8.         public Texture2D textureToSend;
9.         string messageToSend = "Test Message";
10.  
11.         NetworkManager netMan;
12.  
13.         private int reliableChannel;
14.         private int reliableSeqChannel;
15.         private int reliableFragChannel;
16.         private int unreliableChannel;
17.         private int unreliableSeqChannel;
18.  
19.         // Use this for initialization
20.         void Start () {
21.  
22.             ConnectionConfig cc = new ConnectionConfig();
23.  
24.             reliableChannel = cc.AddChannel(QosType.Reliable);
25.             reliableSeqChannel = cc.AddChannel(QosType.ReliableSequenced);
26.             reliableFragChannel = cc.AddChannel(QosType.ReliableFragmented);
27.             unreliableChannel = cc.AddChannel(QosType.Unreliable);
28.             unreliableSeqChannel = cc.AddChannel(QosType.UnreliableSequenced);
29.             cc.PacketSize = 1440;
30.  
31.             netMan.connectionConfig = cc;
32.  
33.             NetworkManager.singleton.StartHost();
34.             Debug.Log("Server Started.");
35.         }
36.  
37.         public void SendOnButtonPress()
38.         {
39.             SendTexture(textureToSend, messageToSend);
40.         }
41.  
42.         //Call to send the Texture and a simple string message
43.         public void SendTexture(Texture2D texture, string message)
44.         {
45.             TextureMessage msg = new TextureMessage();
46.          
47.             //Convert Texture2D to byte array
48.  
49.             msg.textureBytes = texture.GetRawTextureData();
50.             msg.message = message;
51.  
52.             NetworkServer.SendToAll(MyMsgType.texture, msg);
53.         }
54.     }
55.  

 

AFAIK you can do this via Inspector without any code. Tick Advanced Configuration checkbox.