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The library has many constant definitions that are declared as NAME = 'val', e.g. https://github.com/aio-libs/aiohttp/blob/master/aiohttp/client.py#L161

We need to add Final type hint to let users know that these constants should be considered as immutable (this hint doesn't prevent the actual modification and fully backward compatible).

from typing_extensions import Final  # suppor

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

In my experience, far and away the primary reason to use DatabaseError::downcast_ref() is to check the constraint name. It would be nice not to have to downcast, though:

https://github.com/launchbadge/sqlx/blob/master/sqlx-core/src/error.rs#L146

 pub trait DatabaseError: ... {
    // existing methods omitted

    /// Returns the name of the constraint that triggered the error, if