iOS 11 Large Titles in Xamarin.Forms

NavigationBarRenderer.cs

using System;
using MyApp.iOS;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer(typeof(NavigationPage), typeof(NavigationBarRenderer))]
namespace MyApp.iOS
{
    public class NavigationBarRenderer : NavigationRenderer
    {
        protected override void OnElementChanged(VisualElementChangedEventArgs e)
        {
            base.OnElementChanged(e);

            //https://developer.apple.com/ios/human-interface-guidelines/bars/navigation-bars/
            NavigationBar.PrefersLargeTitles = true;
        }
    }
}