feature: save location

Billing.Shared/Helper.cs

@@ -136,6 +136,17 @@ namespace Billing
         }
 
         public delegate void PropertyValueChanged<TResult, TOwner>(TOwner obj, TResult old, TResult @new);
+
+        public static async Task<PermissionStatus> CheckAndRequestPermissionAsync<T>() where T : Permissions.BasePermission, new()
+        {
+            var status = await Permissions.CheckStatusAsync<T>();
+            if (status != PermissionStatus.Disabled &&
+                status != PermissionStatus.Granted)
+            {
+                status = await Permissions.RequestAsync<T>();
+            }
+            return status;
+        }
     }
 
     public class AsyncLazy<T>