Use Persistent Connections (keep-alive)

[green-watch.org]

Yes that is why I suggested that piece of code that I found.

It looks like your do_headers() is some sort of global function that you might be able to add the content length easily.

However, I am not an advanced or even intermediate PHP programmer so my code might be a bit off. I just found it through Google.

If nobody here knows the answer, you might find a PHP forum through Google and ask on there how to set a PHP header for content-length and see if that influences the results on webpagetest any. I think it should if the content length is set correctly.