Properly save and replay FMLProxyPackets

During recording FMLProxyPackets are converted to S3FPacketCustomPayload
During playback the normal Forge network stack is used to handle these packets

src/main/java/com/replaymod/recording/handler/ConnectionEventHandler.java

@@ -68,8 +68,11 @@ public class ConnectionEventHandler {
             String worldName;
             if(event.isLocal) {
                 worldName = MinecraftServer.getServer().getWorldName();
-            } else {
+            } else if (Minecraft.getMinecraft().getCurrentServerData() != null) {
                 worldName = Minecraft.getMinecraft().getCurrentServerData().serverIP;
+            } else {
+                logger.info("Recording not started as the world is neither local nor remote (probably a replay).");
+                return;
             }
             Channel channel = nm.channel();
             ChannelPipeline pipeline = channel.pipeline();

src/main/java/com/replaymod/recording/packet/PacketListener.java

@@ -165,6 +165,7 @@ public class PacketListener extends ChannelInboundHandlerAdapter {
 
                 if (packet instanceof FMLProxyPacket) {
                     // This packet requires special handling
+                    ((FMLProxyPacket) packet).toS3FPackets().forEach(this::save);
                     super.channelRead(ctx, msg);
                     return;
                 }