{
    "Id": <number>,
    "Value": <json token>, 
    "Type": "<your enum value>",
    "MessageState": 0=Forget, 1=RequestNoForget, 2=ResponseNoForget
}

namespace CSharpExample
{
public interface IMessage
{

}

public class MessageA : IMessage
{
    public int Number {get;set;}
}

public class MessageB : IMessage
{
    public string Text {get;set;}
}

public enum MessageType
{
    Integer=0,
    Text=1
}

... Start registering (server) ...
messager.Register<MessageA>(MessageType.Integer,(e)=>{
    e.Data.Number *= 7;
    if(e.NeedReply)
    {
        m.Reply(e.Data);
    }
});

messager.Register<MessageB>(MessageType.Text,null);

... End registering (server) ...

... Start registering (client) ...
messager.Register<MessageA>(MessageType.Integer,(e)=>{
    e.Data.Number = 55;
    if(e.NeedReply)
    {
        m.Reply(e.Data);
    }
});
messager.Register<MessageB>(MessageType.Text,(e)=>{
    e.Data.Text += " C#";
    if(e.NeedReply)
    {
        m.Reply(e.Data);
    }
});
... End registering (client) ...

... Start initial sending (server) ...
messager.SendMessage(new MessageB(){Text="Hello, World"},(msg)=>{
    //do something with value
});
messager.SendMessage(new MessageA(){Number=8},(msg)=>{
    //do something with value
});
... End initial sending (server) ...

... Start initial sending (client) ...
messager.SendMessage(new MessageA(){Number=6},(msg)=>{
    //do something with value
});
messager.SendMessage(new MessageA(){Number=33});
... End initial sending (client) ...

}

json (client => server) (in an ideal world where messages are sent/received in order, server goes first and json is indented)
{
    "Id": 0,
    "Value": {
        "Text": "Hello, World C#"
    },
    "Type": "Text",
    "MessageState": 2
}
{
    "Id":1,
    "Value":{
        "Number": 55
    }, 
    "Type":"Integer",
    "MessageState": 2
}
//this one is zero because this is the first message originated by client
{
    "Id": 0,
    "Value": {
        "Number":6
    },
    "Type":"Integer",
    "MessageState": 1
}
{
    "Id": 1,
    "Value": {
        "Number": 33,
    },
    "Type": "Integer",
    "MessageType": 0
}

json (server => client) (in an ideal world where messages are sent/received in order, server goes first and json is indented)
{
    "Id": 0,
    "Value": {
        Text: "Hello, World"
    },
    "Type": "Text",
    "MessageState": 1
}
{
    "Id": 1,
    "Value": {
        "Number":8
    },
    "Type":"Integer",
    "MessageState": 1
}
{
    "Id":0,
    "Value":{
        "Number":42
    },
    "Type": "Integer",
    "MessageType": 2
}