improve synchronization for network packet parsing, add NbtType class

build.gradle

@@ -38,8 +38,8 @@ minecraft {
 
 dependencies {
 	minecraft "com.mojang:minecraft:$mcVersion"
-	mappings "net.fabricmc:yarn:$mcVersion.21"
-	modCompile "net.fabricmc:fabric-loader:0.2.0.68"
+	mappings "net.fabricmc:yarn:$mcVersion.34"
+	modCompile "net.fabricmc:fabric-loader:0.2.0.70"
 }
 
 curseforge {

src/main/java/net/fabricmc/fabric/api/util/NbtType.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright (c) 2016, 2017, 2018 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.api.util;
+
+import net.minecraft.nbt.CompoundTag;
+import net.minecraft.nbt.Tag;
+
+/**
+ * NBT type ID constants. Useful for filtering by value type in a few cases.
+ *
+ * @see CompoundTag#containsKey(String, int)
+ * @see Tag#idToString(int)
+ *
+ * For the current list of types, check with {@link Tag#TYPES}.
+ */
+public final class NbtType {
+	public static final int END = 0;
+	public static final int BYTE = 1;
+	public static final int SHORT = 2;
+	public static final int INT = 3;
+	public static final int LONG = 4;
+	public static final int FLOAT = 5;
+	public static final int DOUBLE = 6;
+	public static final int BYTE_ARRAY = 7;
+	public static final int STRING = 8;
+	public static final int LIST = 9;
+	public static final int COMPOUND = 10;
+	public static final int INT_ARRAY = 11;
+	public static final int LONG_ARRAY = 12;
+
+	/**
+	 * Any numeric value: byte, short, int, long, float, double.
+	 *
+	 * @see CompoundTag#containsKey(String, int)
+	 */
+	public static final int NUMBER = 99;
+
+	private NbtType() {
+
+	}
+}

src/main/java/net/fabricmc/fabric/mixin/registry/MixinServerPlayNetworkHandler.java

@@ -36,6 +36,7 @@ public abstract class MixinServerPlayNetworkHandler {
 	@Inject(method = "<init>", at = @At("RETURN"))
 	public void init(MinecraftServer server, ClientConnection connection, ServerPlayerEntity player, CallbackInfo info) {
 		//if (server.isDedicated()) {
+		// TODO: If integrated and local, don't send the packet
 		sendPacket(RegistrySyncManager.createPacket());
 		//}
 	}

src/main/java/net/fabricmc/fabric/registry/RegistrySyncManager.java

@@ -30,6 +30,9 @@ import net.minecraft.util.registry.ModifiableRegistry;
 import net.minecraft.util.registry.Registry;
 
 import java.util.Set;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
 
 public final class RegistrySyncManager {
 	public static final Identifier ID = new Identifier("fabric", "registry/sync");
@@ -51,14 +54,21 @@ public final class RegistrySyncManager {
 	public static void receivePacket(PacketContext context, PacketByteBuf buf) {
 		CompoundTag compound = buf.readCompoundTag();
 
-		context.getTaskQueue().execute(() -> {
-			try {
-				apply(compound, false);
-			} catch (RemapException e) {
-				// TODO: log error properly
-				e.printStackTrace();
-			}
-		});
+		try {
+			context.getTaskQueue().executeFuture(() -> {
+				try {
+					apply(compound, false);
+				} catch (RemapException e) {
+					// TODO: log error properly
+					e.printStackTrace();
+				}
+			}).get(30, TimeUnit.SECONDS);
+		} catch (ExecutionException e) {
+			e.printStackTrace();
+		} catch (InterruptedException | TimeoutException e) {
+			// TODO: better error handling
+			new Exception("Failed to apply received packets in time!", e).printStackTrace();
+		}
 	}
 
 	public static CompoundTag toTag(boolean isClientSync) {