Unload chunks for players

I need to unload chunks for all players on a specific server (without fixing it in the kernel).
I know about the existence of the package FullChunkDataPacket, and that he personally is not sent to the player, sent BatchPacket .
I already tried to get all the packages and check, Is any of the nick FullChunkDataPacket, but I realized that such a package does not come at all. The question is how can unload chunks?

 

PHP:

/** @var Level $level */
/** @var int $x */
/** @var int $z */
$level->unloadChunk($x, $z);


 

the problem is that if a chunk is sent to the player, then it cannot be unloaded

 

What is the reason to do that? Im pretty sure pmmp already handled it nicely