private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.speech.v2.UndeleteCustomClassRequest,
            com.google.cloud.speech.v2.UndeleteCustomClassRequest.Builder,
            com.google.cloud.speech.v2.UndeleteCustomClassRequestOrBuilder>
        getUndeleteCustomClassRequestFieldBuilder() {
      if (undeleteCustomClassRequestBuilder_ == null) {
        if (!(requestCase_ == 16)) {
          request_ = com.google.cloud.speech.v2.UndeleteCustomClassRequest.getDefaultInstance();
        }
        undeleteCustomClassRequestBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.speech.v2.UndeleteCustomClassRequest,
                com.google.cloud.speech.v2.UndeleteCustomClassRequest.Builder,
                com.google.cloud.speech.v2.UndeleteCustomClassRequestOrBuilder>(
                (com.google.cloud.speech.v2.UndeleteCustomClassRequest) request_,
                getParentForChildren(),
                isClean());
        request_ = null;
      }
      requestCase_ = 16;
      onChanged();
      return undeleteCustomClassRequestBuilder_;
    }
<pre>
The UndeleteCustomClassRequest that spawned the Operation.
</pre>

<code>.google.cloud.speech.v2.UndeleteCustomClassRequest undelete_custom_class_request = 16;
</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/OperationMetadata.java