public com.google.cloud.storagebatchoperations.v1.BucketList.Bucket.Builder addBucketsBuilder(
        int index) {
      return getBucketsFieldBuilder()
          .addBuilder(
              index,
              com.google.cloud.storagebatchoperations.v1.BucketList.Bucket.getDefaultInstance());
    }
<pre>
Required. List of buckets and their objects to be transformed. Currently,
only one bucket configuration is supported. If multiple buckets are
specified, an error will be returned.
</pre>

<code>
repeated .google.cloud.storagebatchoperations.v1.BucketList.Bucket buckets = 1 [(.google.api.field_behavior) = REQUIRED];
</code>
java-storagebatchoperations/proto-google-cloud-storagebatchoperations-v1/src/main/java/com/google/cloud/storagebatchoperations/v1/BucketList.java