hack around 0xdead10cc

[r10s]

targets #1202

[r10s]

hm, that does not work as waitForExistingJobsDispatched is itself called from main, so, mainDoneSoFar never gets true. needs some more love ...

[cyBerta]

Why don't you move the completion handler itself to the background queue?

something like:

DispatchQueue.global(qos: .background).async {
            completionHandler(.newData)
}

[r10s]

i just played around a bit with DispatchQueue.global.async in the ios emulator as well as on a real iphone7:

• up to 64 jobs are started concurrently
• jobs are mostly started in the correct order, at least when there is little time between scheduling them
• when the last queued job is done, up to 63 other jobs may still be running.

so, an additional DispatchQueue.global.async around DispatchQueue.main.asyncAfter only makes sense if we assume there are lots of jobs queued. but then, it may make sense.

code used for testing

        for i in 0 ..< 100 {
            usleep(UInt32(i) * 1000)
            logger.info("😇 queuing job \(i)")
            DispatchQueue.global().async {
                logger.info("🟢 job \(i) started")
                usleep(UInt32(i) * 1000*1000)
                logger.info("🔴 job \(i) done")
            }
        }