public Builder mergeGcsSource(
        com.google.cloud.vision.v1p3beta1.ImportProductSetsGcsSource value) {
      if (gcsSourceBuilder_ == null) {
        if (sourceCase_ == 1
            && source_
                != com.google.cloud.vision.v1p3beta1.ImportProductSetsGcsSource
                    .getDefaultInstance()) {
          source_ =
              com.google.cloud.vision.v1p3beta1.ImportProductSetsGcsSource.newBuilder(
                      (com.google.cloud.vision.v1p3beta1.ImportProductSetsGcsSource) source_)
                  .mergeFrom(value)
                  .buildPartial();
        } else {
          source_ = value;
        }
        onChanged();
      } else {
        if (sourceCase_ == 1) {
          gcsSourceBuilder_.mergeFrom(value);
        } else {
          gcsSourceBuilder_.setMessage(value);
        }
      }
      sourceCase_ = 1;
      return this;
    }
<pre>
The Google Cloud Storage location for a csv file which preserves a list
of ImportProductSetRequests in each line.
</pre>

<code>.google.cloud.vision.v1p3beta1.ImportProductSetsGcsSource gcs_source = 1;</code>
java-vision/proto-google-cloud-vision-v1p3beta1/src/main/java/com/google/cloud/vision/v1p3beta1/ImportProductSetsInputConfig.java