a multi-thread ping tool to print fast node from mullvad.net wireguard config zip file for openwrt platform
tested on JDCloud AX6600 running openwrt 24.10+
for example: ./mullvad-ping mullvad_wireguard_linux_all_all.zip jp
this command to test all wireguard node start with 'jp' in mullvad_wireguard_linux_all_all.zip