Summary:
Fix use_after_free bug in async_io MultiReads when underlying FS enabled kFSBuffer. kFSBuffer is when underlying FS pass their own buffer instead of using RocksDB scratch in FSReadRequest
Since it's an experimental feature, added a hack for now to fix the bug.
Planning to make public API change to remove const from the callback as it doesn't make sense to use const.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/11645
Test Plan: tested locally
Reviewed By: ltamasi
Differential Revision: D47819907
Pulled By: akankshamahajan15
fbshipit-source-id: 1faf5ef795bf27e2b3a60960374d91274931df8d