What is requestStart?
- requestStart is the moment the browser requests the current document from the server, relevant application caches, or from local resources.
Why measure requestStart?
RequestStart is the starting point of a HTTP request / response transaction.
Everything that has happened before the requestStart time involved finding the resource and establishing a connection. When we reach requestStart is when the HTTP request for a resource actually takes place.
Establishing a start point for the request / response will allow us to examine the HTTP process with precision.
What happened just before requestStart?
Just prior to the requestStart, we established a TCP connection.
What happens immediately after requestStart?
Assuming all goes well, the next step is receiving the response / retrieval of the resource.
The next timestamp in a typical network request will be responseStart.