messengerapi/code/MessengerApi/Models/Http/SendRequest.cs

namespace MessengerApi.Models.Http
{
    public class SendRequest
    {
        public Guid? ToUserId { get; set; }

        public string Payload { get; set; }

        public string PayloadType { get; set; }

        public int? PayloadLifetimeInSeconds { get; set; }
    }
}