private com.google.protobuf.SingleFieldBuilderV3<
            com.google.protobuf.Timestamp,
            com.google.protobuf.Timestamp.Builder,
            com.google.protobuf.TimestampOrBuilder>
        getUpdateTimeFieldBuilder() {
      if (updateTimeBuilder_ == null) {
        updateTimeBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.protobuf.Timestamp,
                com.google.protobuf.Timestamp.Builder,
                com.google.protobuf.TimestampOrBuilder>(
                getUpdateTime(), getParentForChildren(), isClean());
        updateTime_ = null;
      }
      return updateTimeBuilder_;
    }
<pre>
The last update time of the operation.
</pre>

<code>.google.protobuf.Timestamp update_time = 3;</code>
java-translate/proto-google-cloud-translate-v3/src/main/java/com/google/cloud/translate/v3/DeleteDatasetMetadata.java