HTTP HTTP GET Alt-Svc NO_RETRY alt-svc Debug http alt-svc no-retry due to CURLALTSVC_NO_RETRY flag lib%TESTNUMBER http://%HOSTIP:%HTTPPORT/%TESTNUMBER h1 %HOSTIP %HTTPPORT h1 %HOSTIP %NOLISTENPORT "20290222 22:19:28" 0 0 CURL_ALTSVC_HTTP="yeah" 52