shared std.signals

[Joshua Niehus]

Is it possible to create a shared signal class?
I  would like to create a shared signal class so some other 
process that knows certain things can come along emit its info to 
any observer:

import std.stdio, std.signals;

class Observer {
     void watch(string msg) {
         writeln(msg);
     }
}

class Foo {
     string value() {
         return _value;
     }

     string value(string v) {
         if (v != _value) {
             _value = v;
             emit(_value);
         }
         return v;
     }

     mixin Signal!(string);

private:
     string _value;
}

shared Foo a;
void main() {
     a = new shared Foo();
     Observer o1 = new Observer();
     a.connect(&o1.watch);
}