Make elapsed time available in the response event hook

[joaonc]

There are two types of elapsed time on a response:

• The current .elapsed that accounts for total time of request, including event hooks. This is what we have now (Related to https://github.com/encode/httpx/issues/655).
• The elapsed time of the actual request, not taking into account the event hooks, which can take a significant amount of time, depending on what you're doing. This number is currently not available.

In many scenarios, we have request and/or response event hooks that do a time consuming process, but need the time of the actual request only, w/o event hooks. Prime example is logging the response in a response event hook and we want to include the elapsed time in the response.

Is it possible to add a mechanism in which:

• We can access the elapsed time w/o the time to process event hooks.
• Have that time available in the response hook.

[lovelydinosaur]

Options here...

• track your time usage inside the event hooks.
• consider the "trace" extension for more granualar time tracking.

[arseniiarsenii]

Here's a workaround I found:

elapsed_time_seconds: float = response.stream._timer.sync_elapsed()  # If you're using a sync client
elapsed_time_seconds: float = await response.stream._timer.async_elapsed()  # If you're using an async client

This is basically what Response.elapsed property uses under the hood.

Using trace extension for this application is definitely an overkill + it's not really documented. Wasted hours going this route, sharing this solution so other people can save time.

[lovelydinosaur]

Using trace extension for this application is definitely an overkill + it's not really documented. Wasted hours going this route, sharing this solution so other people can save time.

See also #3012