Question on shared memory concurrency

[Richard (Rikki) Andrew Cattermole]

A way to do this without spawning threads manually:

```d
import std.parallelism : TaskPool, parallel, taskPool, defaultPoolThreads;
import std.stdio : writeln;
import std.range : iota;

enum NSWEPT = 1_000_000;
enum NCPU = 4;

void main() {
     import core.atomic : atomicLoad, atomicOp;

     shared(uint) value;

     defaultPoolThreads(NCPU);
     TaskPool pool = taskPool();

     foreach(_; pool.parallel(iota(NSWEPT))) {
         atomicOp!"+="(value, 1);
     }

     writeln(pool.size);
     writeln(atomicLoad(value));
}
```

Unfortunately I could only use the default task pool, creating a new one 
took too long on run.dlang.io.

I also has to decrease NSWEPT because anything larger would take too long.