How to debug slowness of remote calls?

This is a good article: https://blog.cloudflare.com/a-question-of-timing/

This is my .curlrc file:

--write-out "dnslookup: %{time_namelookup} | connect: %{time_connect} | appconnect: %{time_appconnect} | pretransfer: %{time_pretransfer} | starttransfer: %{time_starttransfer} | total: %{time_total} | size: %{size_download}\n"

Run this curl

curl -so /dev/null https://www.zasag.mn

Return:

dnslookup: 0.001954 | connect: 0.190508 | appconnect: 0.000000 | pretransfer: 0.000000 | starttransfer: 0.000000 | total: 0.382312 | size: 0