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>
Output only. Time when this workstation was most recently updated.
</pre>

<code>
.google.protobuf.Timestamp update_time = 7 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-workstations/proto-google-cloud-workstations-v1beta/src/main/java/com/google/cloud/workstations/v1beta/Workstation.java