Using Fiddler2 / Charles in PHP

How can Fiddler2 be u开发者_Python百科sed in an automated fashion inside of a PHP web service to capture request headers and send them to other parts of my PHP code? I found out the fact that it can be automated inside PHP (http://www.fiddler2.com/Fiddler/help/hookup.asp#Q-PHP) but I couldn't find an implementation. Charles seems easier and more obvious to get up an running for this task using the web interface but Fiddler2 is free of course. Any additional links or info would be very helpful.

Also, I see these are primarily debugging tools but is there a reason one would advice using them in production code for scale and thousands of requests per minute?