The Network timeline allows you to see and analyze the network requests that make up each individual page load within a single user's session. In our case we're giving you a network timeline of an ad load. You can use this view to investigate the causes of slow ads and identify performance bugs.When we talk about "requests" in the context of the network timeline, we mean the line-by-line calls for the files that build an ad or send information from the browser to another system. Any given ad in your visitor's session may make requests for:
HTML (the document that frames out the structure and content of a web page)
Fonts (typography and icon sets)
CSS (styles)
JavaScript (scripts that make the page interactive or send data to other systems)
Media (images and videos)