@java.lang.Override
  public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(name_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 1, name_);
    }
    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(displayName_)) {
      com.google.protobuf.GeneratedMessageV3.writeString(output, 2, displayName_);
    }
    if (((bitField0_ & 0x00000001) != 0)) {
      output.writeMessage(3, getIndexTime());
    }
    if (((bitField0_ & 0x00000002) != 0)) {
      output.writeMessage(4, getIndexError());
    }
    getUnknownFields().writeTo(output);
  }
<pre>
Output only. If there was an error with indexing the product set, the field
is populated.

This field is ignored when creating a ProductSet.
</pre>

<code>.google.rpc.Status index_error = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
java-vision/proto-google-cloud-vision-v1/src/main/java/com/google/cloud/vision/v1/ProductSet.java