1. 打印线程

// 打印当前线程标识
 Console.WriteLine($"-------- {Thread.CurrentThread.ManagedThreadId}");
Console.WriteLine(string.Format("-------- {0},{1}", Thread.CurrentThread.ManagedThreadId, 123));

2. 从子/主线程跳回主线程执行任务,例如刷新UI

Device.BeginInvokeOnMainThread

                    Task.Delay(3000).ContinueWith((b) =>
                    {
                        Device.BeginInvokeOnMainThread(() =>
                        {
                            TriangleImage.TranslateTo(viewModel.UiModel.IndicatorWidth * 0.5, 0);
                        });
                    });