Fix log spam with multiple calls to combinedItemApiProvider (Fabric…

…MC#3387)

fabric-transfer-api-v1/src/main/java/net/fabricmc/fabric/impl/transfer/fluid/CombinedProvidersImpl.java

@@ -82,10 +82,14 @@ public Storage<FluidVariant> find(ItemStack itemStack, ContainerItemContext cont
 	}
 
 	public static Event<FluidStorage.CombinedItemApiProvider> getOrCreateItemEvent(Item item) {
-		// register here is thread-safe, so the query below will return a valid provider (possibly one registered before or from another thread).
-		FluidStorage.ITEM.registerForItems(new Provider(), item);
 		ItemApiLookup.ItemApiProvider<Storage<FluidVariant>, ContainerItemContext> existingProvider = FluidStorage.ITEM.getProvider(item);
 
+		if (existingProvider == null) {
+			FluidStorage.ITEM.registerForItems(new Provider(), item);
+			// The provider might not be new Provider() if a concurrent registration happened, re-query.
+			existingProvider = FluidStorage.ITEM.getProvider(item);
+		}
+
 		if (existingProvider instanceof Provider registeredProvider) {
 			return registeredProvider.event;
 		} else {