Add a new SequenceAcquisition event signals

[fdrgsp]

This PR adds three new SequenceAcquisition event signals:

startContinuousSequenceAcquisition = Signal() # when continuousSequenceAcquisition is started
startSequenceAcquisition = Signal(str, int, float, bool) # when SequenceAcquisition is started
stopSequenceAcquisition = Signal(str) # when (Continuous)SequenceAcquisition is stopped

and three methods to the core to implement the above signals:

• startContinuousSequenceAcquisition()
• startSequenceAcquisition()
• stopSequenceAcquisition()

linked to PR https://github.com/tlambert03/napari-micromanager/pull/148

[codecov]

Codecov Report

Merging #115 (78b7995) into main (667d92f) will increase coverage by 0.22%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #115      +/-   ##
==========================================
+ Coverage   88.45%   88.68%   +0.22%     
==========================================
  Files          33       33              
  Lines        1447     1476      +29     
==========================================
+ Hits         1280     1309      +29     
  Misses        167      167              

Impacted Files	Coverage Δ
pymmcore_plus/core/_mmcore_plus.py	90.10% <100.00%> (+0.57%)	⬆️
pymmcore_plus/core/events/_protocol.py	90.62% <100.00%> (+0.96%)	⬆️
pymmcore_plus/core/events/_psygnal.py	100.00% <100.00%> (ø)
pymmcore_plus/core/events/_qsignals.py	100.00% <100.00%> (ø)

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[ianhi]

oooh actually what do you think about adding this directly to MMCore? I'lll ask over there as well.

[ianhi]

See micro-manager/mmCoreAndDevices#179 - even if they do get added there we will need to make some changes here.

Having looked at that little more carefully I also think we probably can't get away with just one signal here. I think we need both a started and stopped signal are necessary as we should have the parameters of the startedsequence emitted in the started signal.

We also need to be careful here to maintain the typing overloads on startSequenceAcquistion:

https://github.com/micro-manager/pymmcore/blob/5fb6ad14a57d2b10b57d04bc7706ff56f1162c9c/pymmcore/__init__.pyi#L924-L931

which should also get re-implemented here to as they will emit different signals than the continuous variant. Difference are somewhat described here: micro-manager/mmCoreAndDevices#171 (comment) also helpful to look directly at the implementations:

startSequenceAcquisition
startContinuousSequenceAcquisition

[tlambert03]

I agree with all of @ianhi's comments. Also think we can add this before any upstream changes are made... (but, it would be ideal if we could somehow anticipate the exact event/callback names that might be used upstream so our API wouldn't change).

I also agree about the typing of the methods, and also think that we should just use the same method names (rather than Sequence -> Seq

[tlambert03]

plus... tests :)