Thread GC non "stop-the-world"

[Kagamin via Digitalmars-d]

On Tuesday, 23 September 2014 at 00:15:51 UTC, Oscar Martin wrote:
> http://blog.mgm-tp.com/2014/04/controlling-gc-pauses-with-g1-collector
>
> (*) What if:
> - It is forbidden for "__gshared" have references/pointers to 
> objects allocated by the GC (if the compiler can help with this 
> prohibition, perfect, if not the developer have to know what he 
> is doing)
> - "shared" types are not allocated by the GC (they could be 
> reference counted or manually released or ...)
> - "immutable" types are no longer implicitly "shared"
>
> In short, the memory accessible from multiple threads is not 
> managed by the GC.

A use case, which comes to mind: a game saves progress to the 
server, the main thread prepares data to be saved (a relatively 
lightweight operation) and hands it over to another thread, which 
saves the data in background. How would you do it?