background processing some submits go missing

[HumptyNumpty]

It would appear some submitted jobs are not being processed
The same problem occurs if the sleep statement is replaced by a compute bound task - discard sum(toSeq(0 .. 100_000_000))
Silly code below

serving
new req 1
new req 2
new req 3
processing job 1
new req 4
new req 5
new req 6
processing job 2
processing job 3
new req 7
processing job 4
processing job 6
processing job 7

#Code

import
    asynchttpserver,
    asyncdispatch,
    std/[atomics, os],
    weave


# ctrl-c interupt handling
type EKeyboardInterrupt = object of OSError

 
proc handler() {.noconv.} =
    raise newException(EKeyboardInterrupt, "Keyboard Interrupt")
 
setControlCHook(handler)


# GLOBALS
var shutdownWeave: Atomic[bool]
shutdownWeave.store(false, moRelaxed)

var executorThread: Thread[ptr Atomic[bool]]
executorThread.runInBackground(Weave, shutdownWeave.addr)

var reqnum: int


# fn submit to weave
proc display_int(x: int): bool =
    sleep(1000)
    echo "processing job " & $x
    return true


# request callback
proc cb(req: Request) {.async.} =
    inc(reqnum)

    echo "new req " & $reqnum
    let ok = submit display_int(reqnum)
    
    await req.respond(Http200, "Hello World " & $reqnum)


proc serve() =    
    setupSubmitterThread(Weave)
    waitUntilReady(Weave)

    var server = newAsyncHttpServer()
    waitFor server.serve(Port(8080), cb)


proc cleanup() = 
    echo "\n\rcleaning up"
    echo "shutting down weave"
    shutdownWeave.store(true)
    

when isMainModule:

    echo "serving"
    try:
        serve()
    except EKeyboardInterrupt:
        cleanup()

    echo "end"