papermc/patches/server/0179-Disable-Explicit-Network-Manager-Flushing.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Sun, 11 Mar 2018 14:13:33 -0400
Subject: [PATCH] Disable Explicit Network Manager Flushing

This seems completely pointless, as packet dispatch uses .writeAndFlush.

Things seem to work fine without explicit flushing, but incase issues arise,
provide a System property to re-enable it using improved logic of doing the
flushing on the netty event loop, so it won't do the flush on the main thread.

Renable flushing by passing -Dpaper.explicit-flush=true

diff --git a/src/main/java/net/minecraft/network/Connection.java b/src/main/java/net/minecraft/network/Connection.java
index 2c807e8a579de5152f99c75ea272a6483a778f17..837cc21af01e691eb9e877479a67ce94d5b2bc06 100644
--- a/src/main/java/net/minecraft/network/Connection.java
+++ b/src/main/java/net/minecraft/network/Connection.java
@@ -136,6 +136,7 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
     // Paper start - NetworkClient implementation
     public int protocolVersion;
     public java.net.InetSocketAddress virtualHost;
+    private static boolean enableExplicitFlush = Boolean.getBoolean("paper.explicit-flush");
     // Paper end
 
     public Connection(PacketFlow side) {
@@ -430,7 +431,7 @@ public class Connection extends SimpleChannelInboundHandler<Packet<?>> {
         }
 
         if (this.channel != null) {
-            this.channel.flush();
+            if (enableExplicitFlush) this.channel.eventLoop().execute(() -> this.channel.flush()); // Paper - we don't need to explicit flush here, but allow opt in incase issues are found to a better version
         }
 
         if (this.tickCount++ % 20 == 0) {