refactor sync engine

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 89.65517% with 6 lines in your changes missing coverage. Please review.

Project coverage is 77.54%. Comparing base (6e6d89c) to head (778c0e8).

Files	Patch %	Lines
libs/infinity_emb/infinity_emb/sync_engine.py	89.65%	6 Missing :warning:

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Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #282 +/- ## ======================================= Coverage 77.53% 77.54% ======================================= Files 35 35 Lines 2506 2507 +1 ======================================= + Hits 1943 1944 +1 Misses 563 563 ```

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