Program crash: GC destroys an object unexpectedly

[eugene]

On Thursday, 23 September 2021 at 15:56:16 UTC, Steven 
Schveighoffer wrote:
> See more details:
>
> https://docs.microsoft.com/en-us/dotnet/api/system.gc.keepalive?view=net-5.0#remarks

"
This method references the obj parameter, making that object 
ineligible for garbage collection from the start of the routine 
to the point, in execution order, where this method is called. 
Code this method at the end, not the beginning, of the range of 
instructions where obj must be available.
"

**Code this method at the end...**

:)
it is the same as proposed by jfondren simple
writeln(stopper.sg0.number) in the end of main, right?