Minecraft 1.16 packet handler exmaple

Packets.java

import ca.teamdman.sfm.SFM;
import java.util.function.Supplier;
import net.minecraft.network.PacketBuffer;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.network.NetworkEvent.Context;
import net.minecraftforge.fml.network.NetworkRegistry;
import net.minecraftforge.fml.network.simple.SimpleChannel;

class Scratch {

	private static final String CHANNEL_NAME = "main";
	private static final String PROTOCOL_VERSION = "1";
	public static final SimpleChannel INSTANCE = NetworkRegistry.newSimpleChannel(
		new ResourceLocation(SFM.MOD_ID, CHANNEL_NAME),
		() -> PROTOCOL_VERSION,
		PROTOCOL_VERSION::equals,
		PROTOCOL_VERSION::equals
	);

	public static void main(String[] args) {
		int id = 0;
		INSTANCE.registerMessage(
			id++,
			MyPacket.class,
			MyPacket::encode,
			MyPacket::decode,
			MyPacket::handle
		);
	}
	
	public static void updateProgress(int prog) {
		INSTANCE.sendToServer(new MyPacket(prog));
	}

	public static class MyPacket {

		int progress;

		public MyPacket(int progress) {
			this.progress = progress;
		}

		public static void encode(MyPacket packet, PacketBuffer buf) {
			buf.writeInt(packet.progress);
		}

		public static MyPacket decode(PacketBuffer buf) {
			return new MyPacket(buf.readInt());
		}

		public static void handle(MyPacket msg, Supplier<Context> ctx) {
			ctx.get().enqueueWork(()-> {
				System.out.println("Progress is now " + msg.progress);
			})
		}
	}
}