Add ProtocolManager#hasLoadedMappings

api/src/main/java/com/viaversion/viaversion/api/protocol/ProtocolManager.java

@@ -311,4 +311,11 @@ public interface ProtocolManager {
      */
     @Deprecated
     PacketWrapper createPacketWrapper(int packetId, @Nullable ByteBuf buf, UserConnection connection);
+
+    /**
+     * Returns whether the mappings have been loaded and the mapping loader executor shutdown.
+     *
+     * @return whether the mappings have been loaded
+     */
+    boolean hasLoadedMappings();
 }

common/src/main/java/com/viaversion/viaversion/protocol/ProtocolManagerImpl.java

@@ -503,6 +503,11 @@ public class ProtocolManagerImpl implements ProtocolManager {
         return new PacketWrapperImpl(packetId, buf, connection);
     }
 
+    @Override
+    public boolean hasLoadedMappings() {
+        return mappingsLoaded;
+    }
+
     public void shutdownLoaderExecutor() {
         Preconditions.checkArgument(!mappingsLoaded);