public com.google.protobuf.Timestamp.Builder getStartTimeBuilder() {
      bitField0_ |= 0x00000002;
      onChanged();
      return getStartTimeFieldBuilder().getBuilder();
    }
<pre>
The start time of the operation.
</pre>

<code>.google.protobuf.Timestamp start_time = 2;</code>
java-visionai/proto-google-cloud-visionai-v1/src/main/java/com/google/cloud/visionai/v1/IndexAssetMetadata.java