private com.google.protobuf.MapField<java.lang.String, java.lang.String>
        internalGetMutableLabels() {
      if (labels_ == null) {
        labels_ = com.google.protobuf.MapField.newMapField(LabelsDefaultEntryHolder.defaultEntry);
      }
      if (!labels_.isMutable()) {
        labels_ = labels_.copy();
      }
      bitField0_ |= 0x00000008;
      onChanged();
      return labels_;
    }
<pre>
Output only. The update timestamp.
</pre>

<code>
.google.protobuf.Timestamp update_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/Channel.java