Help with Concurrency

[Dmitri via Digitalmars-d-learn]

On Tuesday, 3 November 2015 at 23:16:59 UTC, bertg wrote:
> I am having trouble with a simple use of concurrency.
>
> Running the following code I get 3 different tid's, multiple 
> "sock in" messages printed, but no receives. I am supposed to 
> get a "received!" for each "sock in", but I am getting hung up 
> on "receiving...".
>
> [...]

I had a similarily odd experience with std.concurrency - my 
receive would not work unless I also received on Variant, 
although the Variant receiver was a no-op:

  receive(
       (Event event)
       {
           // handle event
       },
       (Variant v) {}
  );