Jaký je rozdíl mezi voláním

    
                this.ConfigureClient(this.Client, this.token);
                try
                {
                    var task = await this.Client.PostAsJsonAsync(WebApiQuery.SyncAddressBook, new AddressBookXmlSync() { XmlXontent = addressBookXml });
                }
                catch (AggregateException ex)
                {
                    Console.WriteLine(ex);
                }

a tímto způsobem ?

                
                this.ConfigureClient(this.Client, this.token);
                var task = this.Client.PostAsJsonAsync(WebApiQuery.SyncAddressBook, new AddressBookXmlSync() { XmlXontent = addressBookXml });
                task.ContinueWith(ExceptionHandler, TaskContinuationOptions.OnlyOnFaulted);

                try
                {
                    task.Wait();
                    var result = task.Result;
                }
                catch (AggregateException ex)
                {
                    Console.WriteLine(ex);
                }