When hosting as Windows Service, Singletons are disposed AFTER the Service has reported to be stopped

Is there an existing issue for this?

[X] I have searched the existing issues

Describe the bug

Pretty much what the title describes. It appears that the Service does wait for IHostedService implementations to finish before reporting the status as stopped, but NOT for IDisposable (or IASyncDisposable) singletons.

This has an awkward side-effect when Restarting the WindowsService as the previous process singleton instances may still be around when new singletons are instantiated in the newly launched process.

Expected Behavior

I would have expected that the service would wait until all singletons are disposed (within some timeout-limit) before reporting the Service as Stopped.

Steps To Reproduce

The repository at https://github.com/lucas-natraj/dueling-services represents a minimal setup to reproduce the issue.

build the solution -> resulting in the executable binary Lastly.exe
register the exe as a windows service using sc.exe create Lastly binPath= {path-to-lastly.exe}
install seq for view aggregated logs. or monitor the log***.txt files in the executable directory.
start the service (via TaskManager)
hit the webapi endpoint by visiting http://localhost:5000/ping.
Restart the window service (via TaskManager)
view logs

The aggregated logs in Seq show the service reporting as stopped before the Ping singleton is disposed. Additionally it can be seen that a new service instance is launched before the singleton from the previous instance has been disposed. Note that the hosted service is appropriately 'cleaned up' before the service reports as stopped.

Exceptions (if any)

No response

.NET Version

6.0.100

Anything else?

dotnet --info

.NET SDK (reflecting any global.json):
 Version:   6.0.100
 Commit:    9e8b04bbff

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19042
 OS Platform: Windows
 RID:         win10-x64
 Base Path:   C:\Program Files\dotnet\sdk\6.0.100\

Host (useful for support):
  Version: 6.0.1
  Commit:  3a25a7f1cc

.NET SDKs installed:
  5.0.401 [C:\Program Files\dotnet\sdk]
  5.0.402 [C:\Program Files\dotnet\sdk]
  6.0.100-rc.2.21505.57 [C:\Program Files\dotnet\sdk]
  6.0.100 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0-rc.2.21480.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0-rc.2.21480.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0-rc.2.21501.6 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

dotnet / aspnetcore