Optimise NetworkManager

[AlfieC]

NetworkManager#sendPacket is an extremely hot piece of code - and in one of the methods called, m(), ConcurrentLinkedQueue#isEmpty is called countlessly. We can cut down on these isEmpty() calls by simply checking if poll() is null.

This is pretty minor, but with the frequency in which sendPacket is called, will add up.

[aikar]

Please redo by simply changing it so its like

NetworkManager.QueuedPacket networkmanager_queuedpacket;
while((networkmanager_queuedpacket = this.i.poll()) != null) {

For this, we don't want to comment out, we want to change the lines to help ensure it conflicts on an update. (Conflicts are good for this)

[AlfieC]

Changed PR to completely eliminate the un-needed packet queue.

[Black-Hole]

This might conflict with #432 @stonar96

[AlfieC]

@Black-Hole this shouldn't conflict because the queue in @stonar96's patch is unused anyway - no idea why it was there to begin with

[Techcable]

It's there to queue packets sent before the player completely connects.
Minecraft is free to call sendPacket() before netty's channel is open and the player's connected.
Instead of removing it completely, maybe you can just set it to null after the player's connected so we don't break anything.

[AlfieC]

After throwing debug checks in all versions, 1.7 -> 1.11, this packet queue has never been used to successfully send a packet.

[zachbr]

Merged with 324acd6

[Black-Hole]

Applying the Anti-Xray-Patch fails very hard here:
https://github.com/PaperMC/Paper/pull/432/files#diff-c15db7ccbd57c4989353f7124f7b6039R1310

[aikar]

@Black-Hole that part can just be removed. As we can see, that change was apparently unneeded to begin with.