restore task return value + add discards

Author: vgromfeld

Microsoft.Toolkit.Uwp.Connectivity/BluetoothLEHelper/ObservableGattDeviceService.cs

@@ -48,7 +48,7 @@ public ObservableGattDeviceService(GattDeviceService service)
             Service = service;
             Name = GattUuidsService.ConvertUuidToName(service.Uuid);
             UUID = Service.Uuid.ToString();
-            PopulateAllCharacteristicsAsync();
+            _ = PopulateAllCharacteristicsAsync();
         }
 
         /// <summary>
@@ -149,7 +149,8 @@ protected virtual void OnPropertyChanged([CallerMemberName] string propertyName
         /// <summary>
         /// Populate the characteristics in <see cref="Characteristics"/>.
         /// </summary>
-        private async void PopulateAllCharacteristicsAsync()
+        /// <returns>The status of the communication with the GATT device.</returns>
+        private async Task<GattCommunicationStatus> PopulateAllCharacteristicsAsync()
         {
             var tokenSource = new CancellationTokenSource(5000);
             var getCharacteristicsTask = await Task.Run(
@@ -166,6 +167,8 @@ private async void PopulateAllCharacteristicsAsync()
                     Characteristics.Add(new ObservableGattCharacteristics(gattCharacteristic, this));
                 }
             }
+
+            return result.Status;
         }
     }
 }

Microsoft.Toolkit.Uwp.SampleApp/Shell.SamplePicker.cs

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Numerics;
+using System.Threading.Tasks;
 using Microsoft.Toolkit.Uwp.SampleApp.Pages;
 using Microsoft.Toolkit.Uwp.UI.Animations;
 using Microsoft.Toolkit.Uwp.UI.Controls;
@@ -35,11 +36,11 @@ private Sample CurrentSample
             set
             {
                 _currentSample = value;
-                SetNavViewSelection();
+                _ = SetNavViewSelectionAsync();
             }
         }
 
-        private async void SetNavViewSelection()
+        private async Task SetNavViewSelectionAsync()
         {
             if (_currentSample != null)
             {
@@ -61,7 +62,7 @@ private void HideSamplePicker()
             SamplePickerGrid.Visibility = Visibility.Collapsed;
             _selectedCategory = null;
 
-            SetNavViewSelection();
+            _ = SetNavViewSelectionAsync();
         }
 
         private async void ShowSamplePicker(Sample[] samples = null, bool group = false)