Crash when immediately switching while a folder is being loaded

Describe the bug When you instantly switch while the folder loads, the app crashes.

To Reproduce Steps to reproduce the behavior:

1. Create a new tab.
2. Click on a large folder pinned on the sidebar
3. Switch two the another tab very fast
4. App will crash

Expected behavior App shouldn’t crash and the refresh task should run in background.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Windows 10 Pro 2004
• App version: v0.13.0 (Downloaded from the Microsoft Store)

Additional context

2020-08-14 14:08:36.7060|ERROR|Files.App|Object reference not set to an instance of an object.|System.NullReferenceException: Object reference not set to an instance of an object.
   at Files.Filesystem.ItemViewModel.UpdateDirectoryInfo() + 0xf0
   at Files.Filesystem.ItemViewModel.<RapidAddItemsToCollectionAsync>d__70.MoveNext() + 0x970
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<>c.<ThrowAsync>b__7_0(Object) + 0x1e
   at System.Action`1.Invoke(T) + 0x28
   at System.Threading.WinRTSynchronizationContext.Invoker.InvokeCore() + 0x33
   at System.Runtime.InteropServices.McgMarshal.ThrowOnExternalCallFailed(Int32, RuntimeTypeHandle) + 0x21
   at __Interop.ComCallHelpers.Call(__ComObject, RuntimeTypeHandle, Int32) + 0xb8
   at __Interop.ForwardComStubs.Stub_11[TThis](__ComObject, Int32) + 0x24
   at Microsoft.AppCenter.Utils.ApplicationLifecycleHelper.<.ctor>b__17_1(Object, UnhandledErrorDetectedEventArgs) + 0x3d
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() + 0x21
   at Microsoft.AppCenter.Utils.ApplicationLifecycleHelper.<.ctor>b__17_1(Object, UnhandledErrorDetectedEventArgs) + 0x75
   at System.EventHandler`1.Invoke(Object, TEventArgs) + 0x2e
   at __Interop.Intrinsics.HasThisCall__23[TArg0](Object, IntPtr, Object, TArg0) + 0x36
   at Files!<BaseAddress>+0x12a44a0

[JaiganeshKumaran]

@gave92 I tried it and it still seems to crash but this time it needs to be done extremely fast (< 50ms). Regular users may not notice it but we should fix it.

[JaiganeshKumaran]

@gave92 But that’s for the recycle bin. I will build the latest branch and try it.