async

First check

• I added a very descriptive title to this issue.
• I used the GitHub search to find a similar issue and didn't find it.
• I searched the FastAPI documentation, with the integrated search.
• I already searched in Google "How to X in FastAPI" and didn't find any information.
• I already read and followed all the tutorial in the docs and didn't find an answ

🐣 Is your feature request related to a problem? Please describe.
We had a report in aiohttp-session (see aio-libs/aiohttp-session#574) that a user submitting a 'large' cookie had the cookie dropped by the receiving browser.

According to RFC 6265 - section 6.1:

General-use user agents SHOULD
provide each of the following minimum

we should have all we need to visualise the scrollbar position in the revlog using draw_scrollbar (like we do in many other widgets)

Not a big deal since I usually have DATABASE_URL in .env anyways, but I just noticed in a new project before creating .env that sqlx mig add init failed with

error: The DATABASE_URL environment variable must be set

Which there doesn't seem to be a good reason for.

Stitching API

Opencv provide a Stitching module/API

Bascially, i would like to be able to rewrite stitching_detailed.cpp in javascript

This includes :

• Stitcher class
• Features extractors (already implemented in opencv4nodejs)
• Estimator

What should happen if deliver_cancel raises an exception? In the current implementation, the shielded cancel scope will prevent it from propagating until the process exits, which might take a while if the crash occurred before signaling the process in any way. Maybe on exception from a user-specified deliver_cancel we should call the default deliver_cancel to kill the process? Or just kill() since