Add Form.ShowAsync

src/Eto/Forms/Form.cs

@@ -97,6 +97,18 @@ public void Show()
 			base.Visible = true;
 		}
 	}
+
+	/// <summary>
+	/// Shows the form with a task that can be awaited until it is closed
+	/// </summary>
+	/// <returns>Task that completes when the form is closed.</returns>
+	public Task ShowAsync()
+	{
+		var tcs = new TaskCompletionSource<bool>();
+		Closed += (sender, e) => tcs.TrySetResult(true);
+		Show();
+		return tcs.Task;
+	}
 
 	/// <summary>
 	/// Interface handler for the <see cref="Form"/> control

test/Eto.Test/UnitTests/Forms/FormTests.cs

@@ -7,13 +7,7 @@ public class FormTests : WindowTests<Form>
 	protected override void Test(Action<Form> test, int timeout = 4000) => Form(test, timeout);
 	protected override void ManualTest(string message, Func<Form, Control> test) => ManualForm(message, test);
 	protected override void Show(Form window) => window.Show();
-	protected override Task ShowAsync(Form window)
-	{
-		var tcs = new TaskCompletionSource<bool>();
-		window.Closed += (sender, e) => tcs.TrySetResult(true);
-		window.Show();
-		return tcs.Task;
-	}
+	protected override Task ShowAsync(Form window) => window.ShowAsync();
 
 	[Test, ManualTest]
 	public void WindowShouldCloseOnLostFocusWithoutHidingParent()