Sending immutable classes using std.concurrency

[Martin]

Can someone tell me what's wrong with this code?
http://dpaste.dzfl.pl/9ff4271f866c

I'm trying to send an immutable instance of a class to another 
thread using the send and receive functions in std.concurrency.
I've already searched and found someone talking about std.variant 
being bugged. Has this still not been fixed, or is my code wrong?