Await, SynchronizationContext WPF

AsyncPump.cs

using System; 
using System.Threading; 
using System.Threading.Tasks; 
using System.Windows.Threading; 

public static class AsyncPump 
{ 
    public static void Run(Func<Task> func) 
    { 
        if (func == null) throw new ArgumentNullException("func"); 

        var prevCtx = SynchronizationContext.Current; 
        try 
        { 
            var syncCtx = new DispatcherSynchronizationContext(); 
            SynchronizationContext.SetSynchronizationContext(syncCtx); 

            var t = func(); 
            if (t == null) throw new InvalidOperationException(); 

            var frame = new DispatcherFrame(); 
            t.ContinueWith(_ => { frame.Continue = false; }, 
                TaskScheduler.Default); 
            Dispatcher.PushFrame(frame); 

            t.GetAwaiter().GetResult(); 
        } 
        finally 
        {  
            SynchronizationContext.SetSynchronizationContext(prevCtx); 
        } 
    } 
}