Add a SIGKILL to second ctrl+c

[ahopkins]

Hitting ctrl+c sends SIGINT to do a graceful shutdown on each worker process. Subsequent ctrl+c currently do nothing.

This PR adds functionality so that the second ctrl+c will send a SIGKILL to the processes for immediate shutdown.

[codecov]

Codecov Report

Base: 88.614% // Head: 88.456% // Decreases project coverage by -0.157% ⚠️

Coverage data is based on head (fa92475) compared to base (db39e12).
Patch coverage: 20.000% of modified lines in pull request are covered.

❗ Current head fa92475 differs from pull request most recent head dce6c26. Consider uploading reports for the commit dce6c26 to get more accurate results

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #2621       +/-   ##
=============================================
- Coverage   88.614%   88.456%   -0.158%     
=============================================
  Files           81        81               
  Lines         6684      6636       -48     
  Branches      1142      1130       -12     
=============================================
- Hits          5923      5870       -53     
- Misses         524       527        +3     
- Partials       237       239        +2     

Impacted Files	Coverage Δ
sanic/worker/manager.py	89.830% <20.000%> (-2.980%)	⬇️
sanic/server/websockets/impl.py	37.557% <0.000%> (-0.922%)	⬇️
sanic/worker/process.py	88.764% <0.000%> (-0.125%)	⬇️
sanic/worker/inspector.py	98.850% <0.000%> (-0.075%)	⬇️
sanic/request.py	94.486% <0.000%> (-0.042%)	⬇️
sanic/worker/multiplexer.py	100.000% <0.000%> (ø)

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[Tronic]

Did you check how this behaves on Windows? IIRC, terminate already works the same as kill, and also KeyboardInterrupt may be received by any of the processes. Also, might consider only handling second Ctrl-C after a slight delay, as it is quite easy to accidentally hit it twice, but this is also not of that much importance (I don't mind if there is no delay required).

[ahopkins]

Did you check how this behaves on Windows? IIRC, terminate already works the same as kill, and also KeyboardInterrupt may be received by any of the processes. Also, might consider only handling second Ctrl-C after a slight delay, as it is quite easy to accidentally hit it twice, but this is also not of that much importance (I don't mind if there is no delay required).

Nope, will check.

[ahopkins]

I realize that is irrelevant since we do this:

if not OS_IS_WINDOWS:
    from signal import SIGKILL
else:
    SIGKILL = SIGINT

For Windows, the behavior is no different than it is today.