refactor(storage): issue upload task to uploader to avoid buffering batches in uploader

[wenym1]

What's changed and what's your intention?

Currently, when we want to upload the shared buffer batches to S3, we need to first send Arc to the write batches to the shared buffer uploader, and then issue Upload commands to tell the uploader to compact the batches and upload the SSTs to S3. Therefore, besides shared buffer, we also store the shared buffer batches in the shared buffer uploader, and this leads to extra work to keep track of the memory usage, and this PR will remove this two-step upload logic, and instead only issue upload tasks, which include the write batches to upload, to the uploader, so that the uploader will not buffer any write batches.

In this PR, we mainly introduce the following change:

• Change the upload logic to issue upload tasks to the uploader and avoid buffering batches in uploader.
• Implement SharedBufferBatchInner, which acts as a guard to the shared buffer batch payload. Whenever the payload is being dropped, it will decrement a global memory usage counter by the batch size. In this way, the memory usage tracking gets easier.
• During initialization of LocalVersionManager, we will pin a hummock version as the initial version, so that we can avoid using Option<LocalVersion> in LocalVersionManager.

Checklist

• I have written necessary docs and comments
• I have added necessary unit tests and integration tests

Refer to a related PR or issue link (optional)

[codecov]

Codecov Report

Merging #2185 (0947a81) into main (1332556) will increase coverage by 0.07%.
The diff coverage is 87.61%.

@@            Coverage Diff             @@
##             main    #2185      +/-   ##
==========================================
+ Coverage   71.02%   71.10%   +0.07%     
==========================================
  Files         657      657              
  Lines       83592    83860     +268     
==========================================
+ Hits        59373    59625     +252     
- Misses      24219    24235      +16     

Flag	Coverage Δ
rust	71.10% <87.61%> (+0.07%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/bench/ss_bench/operations/write_batch.rs	0.00% <0.00%> (ø)
src/storage/src/store.rs	100.00% <ø> (ø)
...rc/hummock/shared_buffer/shared_buffer_uploader.rs	81.73% <72.34%> (-5.77%)	⬇️
src/storage/src/hummock/state_store.rs	74.30% <83.33%> (+2.37%)	⬆️
src/storage/src/hummock/mod.rs	85.54% <85.71%> (-1.37%)	⬇️
src/storage/src/hummock/shared_buffer/mod.rs	90.18% <86.74%> (-4.56%)	⬇️
...e/src/hummock/shared_buffer/shared_buffer_batch.rs	94.16% <88.88%> (-1.47%)	⬇️
src/storage/src/hummock/local_version_manager.rs	89.84% <89.09%> (+0.79%)	⬆️
src/storage/src/hummock/compactor.rs	66.66% <100.00%> (ø)
src/storage/src/hummock/conflict_detector.rs	98.87% <100.00%> (+0.03%)	⬆️
... and 22 more

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[hzxa21]

measure_batch_size will be called again in SharedBufferBatch::new. Can we avoid the recalculation?

[hzxa21]

nits: success_upload_task -> succeed_upload_task