how to check messages read or not on whatsapp API Using C#

Question

function GetNotification() {
debugger;
$.ajax({
type: "POST",
url: "@Url.Action("GetNotification", "GetChat")",
data: "",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (data) {
$('#dvMsg').empty();
debugger;
result = data;
$('#dvMsg').append('');
for (var j = 0; j < result.length; j++) {
$('#dvMsg').append('From:' + result[j].author + ' Message:' + result[j].body + '
');
}
},
error: function (result) {
}
});
}
setInterval(showMessage, "100000");

public JsonResult GetNotification()
{
WebClient client = new WebClient();
client.Headers["Content-type"] = "application/json";
client.Encoding = Encoding.UTF8;
//Testing tt = new Testing();
//tt.lastMessageNumber = "100";
string response_message = client.DownloadString(apiUrl + "messages?token=kzwfwna7auyj5ubp");
Messsage resp = (new JavaScriptSerializer()).Deserialize(response_message);
var data = resp.messages.Where(x => x.chatId == Convert.ToString(Session["ChatId"])).Select(x => new { x.body, x.author, x.time }).OrderBy(x => x.time).ToList();
return Json(data, JsonRequestBehavior.AllowGet);
}