public Builder clearRetrievalMetadata() {
      bitField0_ = (bitField0_ & ~0x00000010);
      retrievalMetadata_ = null;
      if (retrievalMetadataBuilder_ != null) {
        retrievalMetadataBuilder_.dispose();
        retrievalMetadataBuilder_ = null;
      }
      onChanged();
      return this;
    }
<pre>
Optional. Output only. Retrieval metadata.
</pre>

<code>
optional .google.cloud.vertexai.v1.RetrievalMetadata retrieval_metadata = 7 [(.google.api.field_behavior) = OPTIONAL, (.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/GroundingMetadata.java