code: public final void addProductToProductSet(ProductSetName name, ProductName product) {
  
      AddProductToProductSetRequest request =
          AddProductToProductSetRequest.newBuilder()
              .setName(name == null ? null : name.toString())
              .setProduct(product == null ? null : product.toString())
              .build();
      addProductToProductSet(request);
    }
docs: Adds a Product to the specified ProductSet. If the Product is already present, no change is
  made.
  
  <p>One Product can be added to at most 100 ProductSets.
  
  <p>Possible errors:
  
  <p>&#42; Returns NOT_FOUND if the Product or the ProductSet doesn't exist.
  
  <p>Sample code:
  
  <pre><code>
  try (ProductSearchClient productSearchClient = ProductSearchClient.create()) {
  ProductSetName name = ProductSetName.of("[PROJECT]", "[LOCATION]", "[PRODUCT_SET]");
  ProductName product = ProductName.of("[PROJECT]", "[LOCATION]", "[PRODUCT]");
  productSearchClient.addProductToProductSet(name, product);
  }
  </code></pre>
  
  @param name The resource name for the ProductSet to modify.
  <p>Format is: `projects/PROJECT_ID/locations/LOC_ID/productSets/PRODUCT_SET_ID`
  @param product The resource name for the Product to be added to this ProductSet.
  <p>Format is: `projects/PROJECT_ID/locations/LOC_ID/products/PRODUCT_ID`
  @throws com.google.api.gax.rpc.ApiException if the remote call fails