private void ensureProductCategoriesIsMutable() {
      if (!productCategories_.isModifiable()) {
        productCategories_ = new com.google.protobuf.LazyStringArrayList(productCategories_);
      }
      bitField0_ |= 0x00000004;
    }
<pre>
The resource name of a [ProductSet][google.cloud.vision.v1.ProductSet] to
be searched for similar images.

Format is:
`projects/PROJECT_ID/locations/LOC_ID/productSets/PRODUCT_SET_ID`.
</pre>

<code>string product_set = 6 [(.google.api.resource_reference) = { ... }</code>

@param value The bytes for productSet to set.
@return This builder for chaining.
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/ProductSearchParams.java