gistfile1.cs

class Blaat {
  private readonly Waiter<Pion> _pionCompletion = new Waiter<Pion>();
  
  private void PionKlik(Pion item)
  {
    _pionCompletion.Return(item);
  }
  
  public async Task<Pion> KiesPion(Func<Pion, bool> mogelijk)
  {   
      while (true)
      {
          var pion = await _pionCompletion.Wait();
          if (mogelijk(pion))
              return pion;
      }
  }
}