using System;

using Newtonsoft.Json;      

using Newtonsoft.Json.Serialization;

public class Program

{

    public static void Main()

    {

        var payloadAndroid = new

                {

                    data = new

                    {

                        Msg = "22",

                        Id = "11",

                        Type = 0,

                        Badge = 0,

                        sound = "default",

                        Title = "title",

                        Image =  string.Empty,

                        MessageId = string.Empty,

                        PushDirectData = "99"

                    },

                    priority =  "high" 

                };

        Console.WriteLine(JsonConvert.SerializeObject(payloadAndroid, new JsonSerializerSettings()

                {

                    ContractResolver = null

                }));

        Console.WriteLine(JsonConvert.SerializeObject(payloadAndroid, new JsonSerializerSettings()

                {

                    ContractResolver = new CamelCasePropertyNamesContractResolver()

                }));

    }

}