Phase 1: Initial request
Phase 2: Profiling
Phase 3: Delivering optimized code
Once we have determined the usage pattern of the functions in the code, we create a new version which contains only the functions that are used, and replace the other functions with stubs that can be called in real time should they turn out later to be actually required. Requests for this script will be served this optimized version, except for about 5% of requests which will get the instrumented version again as noted above.
The X-Instart-Streaming header also holds information for HTML Streaming. HTML Streaming is covered in the document titled Looking at HTML Streaming Using Instart's Custom Headers and Cookies.
Use browser developer tools to view the request and response headers. (If you don't know how to do this, see the document titled How to Use Browser Developer Tools to Collect the X-Instart-Request-ID Header.) Before you start, clear your browser's cache and cookies so that no stale objects from the browser cache are served.
While the learning period is in effect during phase 2, the following response header is sent:
Once the Instart service has properly learned the website, the following HTTP header is sent: