Optional monitors suggestion

[Walter Bright via Digitalmars-d]

On 5/13/2014 8:46 AM, Yuriy wrote:
> Your feedback is very appreciated. Thanx.

The "_monitor" slot is also used for std.signals. It's been set up in druntime 
to support more than just being a monitor.

We've also considered it for a hook for a reference count (though that design 
had other problems).

I'm not saying your design is wrong, just that we should consider what to do 
with these other issues.