Identity check in F#

Demonstrate identities as used by the request-reply pattern. Run this
program by itself. Note that the utility functions s_ are provided by
zhelpers.fs. It gets boring for everyone to keep repeating this code.

#r @"bin/fszmq.dll"
open fszmq
open fszmq.Context
open fszmq.Socket

#load "zhelpers.fs"

let main () =
use context = new Context(1)

use sink = route context
"inproc://example" |> bind sink

// first allow 0MQ to set the identity
use anonymous = req context
"inproc://example" |> connect anonymous
"ROUTER uses a generated UUID" |> s_send anonymous
s_dump sink

// then set the identity ourself
use identified = req context
(ZMQ.IDENTITY,"Hello"B) |> set identified
"inproc://example" |> connect identified
"ROUTER socket uses REQ's socket identity" |> s_send identified
s_dump sink


main ()