Vertical centring UILabel subclass implementing Xamarin.Forms LabelRenderer

CustomLabelRenderer.cs

using System;
using System.ComponentModel;
using CoreGraphics;
using CustomRendererTest.Controls;
using CustomRendererTest.iOS.Renderers;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

[assembly: ExportRenderer (typeof(CustomLabel), typeof(CustomLabelRenderer))]

namespace CustomRendererTest.iOS.Renderers
{
	public class CustomUILabel
		: UILabel
	{
		public Xamarin.Forms.TextAlignment YAlign { get; set; }

		public override void DrawText (CGRect rect)
		{
			var size = SizeThatFits (Bounds.Size);
			var insets = UIEdgeInsets.Zero;

			if (YAlign == Xamarin.Forms.TextAlignment.Start) {
				BaselineAdjustment = UIBaselineAdjustment.AlignBaselines;

			}
			if (YAlign == Xamarin.Forms.TextAlignment.Center) {
				BaselineAdjustment = UIBaselineAdjustment.AlignCenters;
				insets.Top = (Bounds.Height - size.Height) / 2;
				insets.Bottom = insets.Top;
			}
			if (YAlign == Xamarin.Forms.TextAlignment.End) {
				BaselineAdjustment = UIBaselineAdjustment.AlignBaselines;
				insets.Top = Bounds.Height - size.Height;
			}

			var labelRect = new CGRect (rect.X, rect.Y + insets.Top, rect.Width, rect.Y + size.Height);
			base.DrawText (labelRect);
		}
	}

	public class CustomLabelRenderer
		: ViewRenderer<CustomLabel, CustomUILabel>
	{
		public CustomLabelRenderer ()
		{
		}

		protected override void OnElementChanged (ElementChangedEventArgs<CustomLabel> e)
		{
			base.OnElementChanged (e);

			if (e.NewElement == null) {
				return;
			}
			if (Control == null) {
				var label = new CustomUILabel ();
				label.BackgroundColor = Element.BackgroundColor.ToUIColor ();
				label.Text = Element.Text;
				label.TextColor = Element.TextColor.ToUIColor ();
				label.YAlign = Element.YAlign;
				SetNativeControl (label);
			}
		}

		protected override void OnElementPropertyChanged (object sender, PropertyChangedEventArgs e)
		{
			base.OnElementPropertyChanged (sender, e);
			if (Control == null) {
				return;
			}
			if (e.PropertyName == View.BackgroundColorProperty.PropertyName) {
				Control.BackgroundColor = Element.BackgroundColor.ToUIColor ();
			}
			if (e.PropertyName == Label.TextProperty.PropertyName) {
				Control.Text = Element.Text;
			}
			if (e.PropertyName == Label.TextColorProperty.PropertyName) {
				Control.TextColor = Element.TextColor.ToUIColor ();
			}
			if (e.PropertyName == Label.YAlignProperty.PropertyName) {
				Control.YAlign = Element.YAlign;
			}
			Control.SetNeedsDisplay ();
		}
	}
}