Very very slow loading of Spike data in current dev branch

[KatharineShapcott]

Describe the bug

Went from 180 ms to 9.43 seconds!

This seems to be specific to spike data, here I'm looping through all the data types in a folder and most times are similar:

0.3.dev187
ADC
CPU times: user 7.22 ms, sys: 4.03 ms, total: 11.2 ms
Wall time: 25.6 ms
events
CPU times: user 264 ms, sys: 3.99 ms, total: 268 ms
Wall time: 271 ms
lfp
CPU times: user 2.99 ms, sys: 1.02 ms, total: 4.01 ms
Wall time: 6.57 ms
raw
CPU times: user 4.83 ms, sys: 4 µs, total: 4.84 ms
Wall time: 16.9 ms
spikes
CPU times: user 9.21 s, sys: 214 ms, total: 9.42 s
Wall time: 9.46 s

2022.8.1a0
ADC
CPU times: user 5.93 ms, sys: 0 ns, total: 5.93 ms
Wall time: 7.25 ms
events
CPU times: user 4.68 ms, sys: 713 µs, total: 5.4 ms
Wall time: 5.39 ms
lfp
CPU times: user 2.35 ms, sys: 1.95 ms, total: 4.3 ms
Wall time: 4.17 ms
raw
CPU times: user 3.35 ms, sys: 2.06 ms, total: 5.41 ms
Wall time: 4.88 ms
spikes
CPU times: user 160 ms, sys: 19.9 ms, total: 180 ms
Wall time: 181 ms

Files sizes looks like this:

To Reproduce
Switch to the current dev branch and load in spike data.

Expected behavior
Loading time stays the same as previously.

System Profile:

• OS: ESI cluster

• Please paste the output of the following command here

  import syncopy as spy; spy.AnalogData().log

   >>> SyNCopy v. 0.3.dev187 <<< 
  

Created: Fri Oct 7 18:29:01 2022

System Profile:
3.8.13 (default, Mar 28 2022, 11:38:47)
[GCC 7.5.0]
ACME: 0.21
Dask: 2021.10.0
NumPy: 1.21.2
SciPy: 1.7.3

--- LOG ---

|=== shapcottk@esi-svhpc23: Fri Oct 7 18:29:02 2022 ===|

__init__: created AnalogData object

Additional Information
I don't notice any change in the memory usage and it's not specific to loading with tags.

[tensionhead]

So the problem at hand got solved, however we found unexpected (nTrials^2 + nTrials) scaling of that expensive, and with the fix avoided again, equality check here
We are also wondering why for a simple init of AnalogData the __eq__ operator gets into action in the first place.