How to create custom health monitor to monitor DNS service in GTM/LTM?

I've created a code for the purpose of health monitoring DNS service in GTM/LTM.

 

It took me some time to create it so I thought I might as well share it in this community so that it will not go down to waste.

 

Please feel free to comment if you find any bug or improvement to the code. Hope you guys can benefit from the code.

 

https://devcentral.f5.com/codeshare/custom-dns-service-monitoring-for-gtm-and-ltm-1093

 

Cheerz