Safari无法连接基于SBCL+usocket搭建的极简Web服务器

我正在使用usocket在SBCL中测试一个极简Web服务器，代码如下：

(defun create-server (port)
  (let* ((socket (usocket:socket-listen *hostname* port))
     (connection (usocket:socket-accept socket :element-type 'character)))
    (unwind-protect
     (with-open-stream (stream (usocket:socket-stream connection))
       (progn
         (format stream *htmlstring*)
         (finish-output stream)))
      (progn
        (format t "Closing sockets~%")
        (usocket:socket-close connection)
        (usocket:socket-close socket)))))

该服务器接收指定端口的任意GET请求（未做处理），并返回如下响应：

HTTP/1.1 200 OK
Content-Type: text/html
Connection: close
Content-Length: 64

<!DOCTYPE HTML><html><body><h1>Valid Response</h1></body></html>

我承认这种实现存在协议滥用，但理论上应该可行——它在远程服务器和本地环境中，能被curl、wget等命令行工具，以及MacOS的Firefox、Chrome、Windows的Edge正常访问，唯独Safari不行，报错：
Safari Can’t Connect to the Server
Safari无法打开页面“mysite.net:8080”，因为无法连接到服务器“mysite.net”。

我尝试将*hostname*绑定到域名、IPv4地址及所有IPv4/IPv6接口，Safari Technology Preview曾成功加载一次远程服务器响应，但后续失败。我怀疑Safari发送多个请求（可能先尝试HTTPS，而服务器仅支持HTTP），导致服务器在Safari准备好处理响应前就关闭了连接，但不确定具体原因。我的问题是：让Safari能处理Web服务器响应的最低要求是什么？它似乎比其他工具和浏览器更敏感、限制更多。

更新1 #

我对Chrome（正常）、Firefox（正常）和Safari（异常）分别执行了tcpdump port 8080，虽未发现明显错误，但似乎支持“连接过早关闭”的推测。同时注意到Safari未发送GET请求，而Chrome和Firefox有。为清晰起见，我将时间戳重命名为ts，客户端和服务器名称分别改为client和host。

Chrome #

ts IP client > host: Flags [SEW], seq 534012909, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 1451219412 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [S.E], seq 657848768, ack 534012910, win 65160, options [mss 1460,sackOK,TS val 3784271166 ecr 1451219412,nop,wscale 7], length 0
ts IP client > host: Flags [.], ack 1, win 2058, options [nop,nop,TS val 1451219440 ecr 3784271166], length 0
ts IP client > host: Flags [P.], seq 1:524, ack 1, win 2058, options [nop,nop,TS val 1451219440 ecr 3784271166], length 523: HTTP: GET / HTTP/1.1
ts IP host > client: Flags [P.], seq 1:150, ack 1, win 510, options [nop,nop,TS val 3784271195 ecr 1451219440], length 149: HTTP: HTTP/1.1 200 OK
ts IP host > client: Flags [F.], seq 150, ack 1, win 510, options [nop,nop,TS val 3784271195 ecr 1451219440], length 0
ts IP client > host: Flags [.], ack 150, win 2056, options [nop,nop,TS val 1451219468 ecr 3784271195], length 0
ts IP client > host: Flags [.], ack 151, win 2056, options [nop,nop,TS val 1451219468 ecr 3784271195], length 0
ts IP host > client: Flags [R], seq 657848769, win 0, length 0
ts IP client > host: Flags [F.], seq 524, ack 151, win 2056, options [nop,nop,TS val 1451219468 ecr 3784271195], length 0
ts IP host > client: Flags [R], seq 657848919, win 0, length 0
ts IP host > client: Flags [R], seq 657848919, win 0, length 0
ts IP client > host: Flags [SEW], seq 1710339549, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 3288928666 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [R.], seq 0, ack 1710339550, win 0, length 0

Firefox #

ts IP client > host: Flags [SEW], seq 626413754, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 3625754178 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [S.E], seq 1881453667, ack 626413755, win 65160, options [mss 1460,sackOK,TS val 3784031794 ecr 3625754178,nop,wscale 7], length 0
ts IP client > host: Flags [.], ack 1, win 2058, options [nop,nop,TS val 3625754209 ecr 3784031794], length 0
ts IP host > client: Flags [P.], seq 1:150, ack 1, win 510, options [nop,nop,TS val 3784031824 ecr 3625754209], length 149: HTTP: HTTP/1.1 200 OK
ts IP host > client: Flags [F.], seq 150, ack 1, win 510, options [nop,nop,TS val 3784031824 ecr 3625754209], length 0
ts IP client > host: Flags [.], ack 150, win 2056, options [nop,nop,TS val 3625754239 ecr 3784031824], length 0
ts IP client > host: Flags [.], ack 151, win 2056, options [nop,nop,TS val 3625754239 ecr 3784031824], length 0
ts IP client > host: Flags [P.], seq 1:409, ack 151, win 2056, options [nop,nop,TS val 3625754895 ecr 3784031824], length 408: HTTP: GET / HTTP/1.1
ts IP client > host: Flags [F.], seq 409, ack 151, win 2056, options [nop,nop,TS val 3625754895 ecr 3784031824], length 0
ts IP host > client: Flags [R], seq 1881453818, win 0, length 0
ts IP host > client: Flags [R], seq 1881453818, win 0, length 0

Safari #

ts IP client > host: Flags [SEW], seq 2577772978, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 1558328301 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [S.E], seq 4186102721, ack 2577772979, win 65160, options [mss 1460,sackOK,TS val 3784121701 ecr 1558328301,nop,wscale 7], length 0
ts IP client > host: Flags [.], ack 1, win 2058, options [nop,nop,TS val 1558328335 ecr 3784121701], length 0
ts IP host > client: Flags [P.], seq 1:150, ack 1, win 510, options [nop,nop,TS val 3784121729 ecr 1558328335], length 149: HTTP: HTTP/1.1 200 OK
ts IP host > client: Flags [F.], seq 150, ack 1, win 510, options [nop,nop,TS val 3784121729 ecr 1558328335], length 0
ts IP client > host: Flags [.], ack 151, win 2056, options [nop,nop,TS val 1558328364 ecr 3784121729], length 0
ts IP client > host: Flags [F.], seq 1, ack 151, win 2056, options [nop,nop,TS val 1558328364 ecr 3784121729], length 0
ts IP host > client: Flags [.], ack 2, win 510, options [nop,nop,TS val 3784121758 ecr 1558328364], length 0
ts IP client > host: Flags [SEW], seq 3648579004, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 2532260604 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [R.], seq 0, ack 3648579005, win 0, length 0
ts IP client > host: Flags [SEW], seq 650543579, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 1158948454 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [R.], seq 0, ack 650543580, win 0, length 0
ts IP client > host: Flags [SEW], seq 698782494, win 65535, options [mss 1460,nop,wscale 6,nop,nop,TS val 772224008 ecr 0,sackOK,eol], length 0
ts IP host > client: Flags [R.], seq 0, ack 698782495, win 0, length 0

更新2 #

移除(usocket:socket-close socket)后，Safari可以正常渲染响应，无需手动刷新页面，但这会带来其他服务器问题，待解决后我会发布完整可行方案。

内容的提问来源于stack exchange，提问作者Tambarskjelve