Question for implementing recovery

[loloxwg]

The Bustub instance does not seem to utilize log recovery. There is no initialization of a flush thread, and upon system startup, there are no actions related to undo or redo operations.
Additionally, the current implementation of table_page.cpp does not include any checks for if (enable_logging).
It seems that in a certain commit, there was a comment like this:

/**
 * Removed to support new lock manager API for p4 (multilevel locking); Big hack energy
 * This clause was used in logging and recovery projects previously; not being used right now
 */

Why was it removed? It seems that log_manager->AppendLogRecord is not working now.
For building a disk oriented db, recovery is important part, I think the recovery should be a part of project :)