public Builder clearLlmRanker() {
        if (llmRankerBuilder_ == null) {
          if (rankingConfigCase_ == 3) {
            rankingConfigCase_ = 0;
            rankingConfig_ = null;
            onChanged();
          }
        } else {
          if (rankingConfigCase_ == 3) {
            rankingConfigCase_ = 0;
            rankingConfig_ = null;
          }
          llmRankerBuilder_.clear();
        }
        return this;
      }
<pre>
Optional. Config for LlmRanker.
</pre>

<code>
.google.cloud.vertexai.v1.RagRetrievalConfig.Ranking.LlmRanker llm_ranker = 3 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/RagRetrievalConfig.java