feat: support realtime toggle update via socket.io

[hezean]

realtime toggle update is not supported in python3.5, see miguelgrinberg/python-socketio#589

[SSebo]

Good Job! You are so productive! BTW suggest to separate quotation mark replacement to another PR, to make this PR more focus on socketio part.

[FengShang]

related to #19

[codecov-commenter]

Codecov Report

Merging #20 (b718a67) into main (ac77af4) will increase coverage by 0.29%.
The diff coverage is 71.89%.

@@            Coverage Diff             @@
##             main      #20      +/-   ##
==========================================
+ Coverage   85.64%   85.94%   +0.29%     
==========================================
  Files          34       36       +2     
  Lines        1247     1380     +133     
==========================================
+ Hits         1068     1186     +118     
- Misses        179      194      +15     

Impacted Files	Coverage Δ
featureprobe/internal/deprecated.py	0.00% <0.00%> (ø)
featureprobe/memory_data_repository.py	81.81% <0.00%> (ø)
featureprobe/default_event_processor.py	82.17% <45.83%> (+7.77%)	⬆️
featureprobe/synchronizer.py	68.00% <71.42%> (+1.33%)	⬆️
featureprobe/client.py	85.24% <73.07%> (-9.63%)	⬇️
featureprobe/realtime.py	77.77% <77.77%> (ø)
featureprobe/pooling_synchronizer.py	86.74% <85.00%> (+10.27%)	⬆️
featureprobe/file_synchronizer.py	84.37% <88.88%> (+4.37%)	⬆️
featureprobe/user.py	91.66% <92.30%> (-1.44%)	⬇️
featureprobe/__init__.py	100.00% <100.00%> (ø)
... and 9 more

[hezean]

not used in this pr, but it may be used someday, so keep it?

[hezean]

@dengfeige can we start reviewing this pr? it's functionally equivalent with FeatureProbe/server-sdk-node#6

[hezean]

ci crashed due to py3.5 not found, please help re-trigger it later, thanks

[gangb-tech]

This PR has already been merged into #24.