public Builder setUpdateMask(com.google.protobuf.FieldMask.Builder builderForValue) {
      if (updateMaskBuilder_ == null) {
        updateMask_ = builderForValue.build();
      } else {
        updateMaskBuilder_.setMessage(builderForValue.build());
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
The [FieldMask][google.protobuf.FieldMask] that specifies which fields
to update.
If update_mask isn't specified, all mutable fields are to be updated.
Valid mask paths include `product_labels`, `display_name`, and
`description`.
</pre>

<code>.google.protobuf.FieldMask update_mask = 2;</code>
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/UpdateProductRequest.java