public Builder clearPhraseSet() {
        if (valueCase_ == 1) {
          valueCase_ = 0;
          value_ = null;
          onChanged();
        }
        return this;
      }
<pre>
The name of an existing PhraseSet resource. The user must have read
access to the resource and it must not be deleted.
</pre>

<code>string phrase_set = 1 [(.google.api.resource_reference) = { ... }</code>

@return This builder for chaining.
java-speech/proto-google-cloud-speech-v2/src/main/java/com/google/cloud/speech/v2/SpeechAdaptation.java