//串行异步
serialQueue.async {
sleep(2)
print("serialTask 1" + "(Thread.current) ")
}
serialQueue.async {
print("serialTask 2" + "(Thread.current) ")
}
//并发异步
concurrentQueue.async {
sleep(2)
print("concurrentTask 1" + "(Thread.current) ")
}
concurrentQueue.async {
print("concurrentTask 2" + "(Thread.current) ")
}