串行隊(duì)列：隊(duì)列中的任務(wù)只會(huì)順序執(zhí)行(類似跑步)
dispatch_queue_t q = dispatch_queue_create(“....”, DISPATCH_QUEUE_SERIAL);
并行隊(duì)列：隊(duì)列中的任務(wù)通常會(huì)并發(fā)執(zhí)行(類似賽跑)
dispatch_queue_t q = dispatch_queue_create("......", DISPATCH_QUEUE_CONCURRENT);
全局隊(duì)列：是系統(tǒng)的，直接拿過來（GET）用就可以那先；與并行隊(duì)列類似农猬，但調(diào)試時(shí)，無法確認(rèn)操作所在隊(duì)列
dispatch_queue_t q = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
主隊(duì)列：每一個(gè)應(yīng)用程序?qū)?yīng)唯一一個(gè)主隊(duì)列售淡，直接GET即可斤葱；在多線程開發(fā)中，使用主隊(duì)列更新UI
dispatch_queue_t q = dispatch_get_main_queue();
