Componentizing D's garbage collector

[Nicholas Londey]

In theory you could use a region allocator for a pure function 
and copy its result out.
This wouldn't be worth it in the general case but imagine worker 
threads in a task pool. Pure functions executing message 
in/message(s) out that did not significantly contribute to the 
stop the world GC workload.

My D experience is only limited (mainly a C++ programmer) but 
something along these lines is how I have always imagined GC will 
sidestep the 'stop the world' problem as we move toward 
async/await programming models.