private com.google.protobuf.SingleFieldBuilderV3<
            com.google.cloud.speech.v2.UndeletePhraseSetRequest,
            com.google.cloud.speech.v2.UndeletePhraseSetRequest.Builder,
            com.google.cloud.speech.v2.UndeletePhraseSetRequestOrBuilder>
        getUndeletePhraseSetRequestFieldBuilder() {
      if (undeletePhraseSetRequestBuilder_ == null) {
        if (!(requestCase_ == 20)) {
          request_ = com.google.cloud.speech.v2.UndeletePhraseSetRequest.getDefaultInstance();
        }
        undeletePhraseSetRequestBuilder_ =
            new com.google.protobuf.SingleFieldBuilderV3<
                com.google.cloud.speech.v2.UndeletePhraseSetRequest,
                com.google.cloud.speech.v2.UndeletePhraseSetRequest.Builder,
                com.google.cloud.speech.v2.UndeletePhraseSetRequestOrBuilder>(
                (com.google.cloud.speech.v2.UndeletePhraseSetRequest) request_,
                getParentForChildren(),
                isClean());
        request_ = null;
      }
      requestCase_ = 20;
      onChanged();
      return undeletePhraseSetRequestBuilder_;
    }
<pre>
The UndeletePhraseSetRequest that spawned the Operation.
</pre>

<code>.google.cloud.speech.v2.UndeletePhraseSetRequest undelete_phrase_set_request = 20;
</code>
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/OperationMetadata.java