Flush consolidation

proxy/src/main/java/com/velocitypowered/proxy/connection/backend/VelocityServerConnection.java

@@ -3,12 +3,14 @@ package com.velocitypowered.proxy.connection.backend;
 import static com.velocitypowered.proxy.VelocityServer.GSON;
 import static com.velocitypowered.proxy.connection.forge.legacy.LegacyForgeConstants.HANDSHAKE_HOSTNAME_TOKEN;
 import static com.velocitypowered.proxy.network.Connections.FLOW_HANDLER;
+import static com.velocitypowered.proxy.network.Connections.FLUSH_CONSOLIDATION;
 import static com.velocitypowered.proxy.network.Connections.FRAME_DECODER;
 import static com.velocitypowered.proxy.network.Connections.FRAME_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.HANDLER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_DECODER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.READ_TIMEOUT;
+import static io.netty.handler.flush.FlushConsolidationHandler.DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES;
 
 import com.google.common.base.Preconditions;
 import com.velocitypowered.api.network.ProtocolVersion;
@@ -37,6 +39,7 @@ import io.netty.channel.Channel;
 import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelInitializer;
 import io.netty.handler.flow.FlowControlHandler;
+import io.netty.handler.flush.FlushConsolidationHandler;
 import io.netty.handler.timeout.ReadTimeoutHandler;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
@@ -90,7 +93,9 @@ public class VelocityServerConnection implements MinecraftConnectionAssociation,
                 .addLast(MINECRAFT_DECODER,
                     new MinecraftDecoder(ProtocolUtils.Direction.CLIENTBOUND))
                 .addLast(MINECRAFT_ENCODER,
-                    new MinecraftEncoder(ProtocolUtils.Direction.SERVERBOUND));
+                    new MinecraftEncoder(ProtocolUtils.Direction.SERVERBOUND))
+                .addLast(FLUSH_CONSOLIDATION, new FlushConsolidationHandler(
+                    DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES, true));
           }
         })
         .connect(registeredServer.getServerInfo().getAddress())

proxy/src/main/java/com/velocitypowered/proxy/network/Connections.java

@@ -15,6 +15,7 @@ public class Connections {
   public static final String MINECRAFT_DECODER = "minecraft-decoder";
   public static final String MINECRAFT_ENCODER = "minecraft-encoder";
   public static final String READ_TIMEOUT = "read-timeout";
+  public static final String FLUSH_CONSOLIDATION = "flush-consolidation";
 
   private Connections() {
     throw new AssertionError();

proxy/src/main/java/com/velocitypowered/proxy/network/ServerChannelInitializer.java

@@ -1,5 +1,6 @@
 package com.velocitypowered.proxy.network;
 
+import static com.velocitypowered.proxy.network.Connections.FLUSH_CONSOLIDATION;
 import static com.velocitypowered.proxy.network.Connections.FRAME_DECODER;
 import static com.velocitypowered.proxy.network.Connections.FRAME_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.LEGACY_PING_DECODER;
@@ -7,6 +8,7 @@ import static com.velocitypowered.proxy.network.Connections.LEGACY_PING_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_DECODER;
 import static com.velocitypowered.proxy.network.Connections.MINECRAFT_ENCODER;
 import static com.velocitypowered.proxy.network.Connections.READ_TIMEOUT;
+import static io.netty.handler.flush.FlushConsolidationHandler.DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES;
 
 import com.velocitypowered.proxy.VelocityServer;
 import com.velocitypowered.proxy.connection.MinecraftConnection;
@@ -22,6 +24,7 @@ import com.velocitypowered.proxy.protocol.netty.MinecraftVarintLengthEncoder;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelInitializer;
 import io.netty.handler.codec.haproxy.HAProxyMessageDecoder;
+import io.netty.handler.flush.FlushConsolidationHandler;
 import io.netty.handler.timeout.ReadTimeoutHandler;
 import java.util.concurrent.TimeUnit;
 
@@ -45,7 +48,9 @@ public class ServerChannelInitializer extends ChannelInitializer<Channel> {
         .addLast(LEGACY_PING_ENCODER, LegacyPingEncoder.INSTANCE)
         .addLast(FRAME_ENCODER, MinecraftVarintLengthEncoder.INSTANCE)
         .addLast(MINECRAFT_DECODER, new MinecraftDecoder(ProtocolUtils.Direction.SERVERBOUND))
-        .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolUtils.Direction.CLIENTBOUND));
+        .addLast(MINECRAFT_ENCODER, new MinecraftEncoder(ProtocolUtils.Direction.CLIENTBOUND))
+        .addLast(FLUSH_CONSOLIDATION, new FlushConsolidationHandler(
+            DEFAULT_EXPLICIT_FLUSH_AFTER_FLUSHES, true));
 
     final MinecraftConnection connection = new MinecraftConnection(ch, this.server);
     connection.setSessionHandler(new HandshakeSessionHandler(connection, this.server));