Making a method async in Xamarin (C#)

Issue

I have this method that downloads data from the internet:

    public ObservableCollection<Magnetka> ParseJSON() {
            ObservableCollection<Models.Magnetka> Markers = new ObservableCollection<Models.Magnetka>();
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("(URL)");
            request.Headers.Add("Authentication-Token", "(KEY)");
            request.Method = "GET";
            request.ContentType = "application/json";
            CookieContainer cookieContainer = new CookieContainer();
            request.CookieContainer = cookieContainer;
            var response = request.GetResponse();
            var responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
            ......... JSON parsing)

            return Markers;

Now I found out this isn't too fast and it freezes the app for two seconds or so, so I need to make it async. However, I call the method like this in another class:

        GetMarkers getMarkers = new GetMarkers();
        Markers = getMarkers.ParseJSON();

How can I make my method async? I don't understand the concept well and if I make ParseJSON() async Task, I don't know where to put the "await" keyword. Can anyone help me?

Solution

first, mark the method async and use the async version of GetResponse

public async Task<ObservableCollection<Magnetka>> ParseJSON() 
{
    ...
    var response = await request.GetResponseAsync();
    ...

    return Markers;
}

then when you call it use the await keyword

Markers = await getMarkers.ParseJSON();

Answered By - Jason