feat(storage): enhance RocksDB sync and compression options

[gaius-qi]

Description

This pull request introduces improvements to logging and optimizes the RocksDB storage engine configuration. The most significant changes are the addition of debug logs after write operations and adjustments to RocksDB compression and sync settings to improve performance and observability.

Logging Improvements:

• Added debug logs after successful piece writes in both content_linux.rs and content_macos.rs to indicate completion of write operations. [1] [2]
• Added a debug log in server/tcp.rs after flushing the TCP writer to signal stream completion.

RocksDB Storage Engine Optimization:

• Introduced a new constant DEFAULT_BYTES_PER_SYNC and set RocksDB sync options (set_use_fsync(false) and set_bytes_per_sync) to optimize disk writes. [1] [2]
• Changed the bottommost compression type from Zstd to Lz4 for consistency with the main compression type.
• Updated the write operation to use WriteOptions with sync explicitly set to false, potentially improving write performance.

Related Issue

Motivation and Context

Screenshots (if appropriate)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 47.59%. Comparing base (69f5167) to head (14c219e).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1492      +/-   ##
==========================================
+ Coverage   47.57%   47.59%   +0.02%     
==========================================
  Files          70       70              
  Lines       17724    17731       +7     
==========================================
+ Hits         8432     8439       +7     
  Misses       9292     9292              

Files with missing lines	Coverage Δ
dragonfly-client-storage/src/content_linux.rs	77.59% <ø> (ø)
dragonfly-client-storage/src/server/tcp.rs	0.00% <ø> (ø)
...onfly-client-storage/src/storage_engine/rocksdb.rs	97.42% <100.00%> (+0.03%)	⬆️

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[BruceAko]

LGTM