Enhancement

• Perfect array_walk for coroutine (#2740) (@twose)
• Add Swoole\Constant to replace string (@matyhtf) (@twose)
• Add alias Co::dnsLookup of swoole_async_dns_lookup_coro (42293ef) (@matyhtf)
• Expend default HTTP_FORM_KEYLEN to 512 (#2734) (@sshymko)
• Better dns resolver (c6deff1) (@matyhtf)
• Support HTTP PURGE (#2462) (@sshymko)
• Response 400 for bad request (#2751) (@twose)
• Decoupling sockets and reactor (internal) (@twose)
• Add Timer::set / Process->set / Process\Pool->set (@twose)
• Optional hugepage feature support for FreeBSD (#2757) (@devnexen)

Fixed

• Fixed macOS not support extern thread_local () (@matyhtf)
• Fixed SSL dispatch (#2736) (@matyhtf)
• Fixed aio thread num (#2745) (@matyhtf)
• Fixed async_thread (#2747) (@matyhtf)
• Fixed Swoole\Client::select timeout (#2758) (@LeiZhang-Hunter)
• Fixed empty timer (#2749) (@twose)
• Fixed zlib decompression (#2762) (@twose)