Implementing a POST method

multiplefiles.cs

// IRestClient.cs
[Post ("/posts")]
Task AddPost (Foo foo);

// RestClient.cs
public async Task AddPost (Foo foo)
{
    await _restClient.AddPost (foo);
}

// Code-behind
private async void Handle_Clicked_Awesome_Post (object sender, System.EventArgs e)
{

    var foo = new Foo {
        id = 1337,
        title = "Awesome!",
        body = "Unicorns and rainbows",
        userId = 1
    };

    await _restClient.AddPost (foo);

    ResultLabel.Text = $"Added";
}