private void ensureCacheTokensDetailsIsMutable() {
        if (!((bitField0_ & 0x00000020) != 0)) {
          cacheTokensDetails_ =
              new java.util.ArrayList<com.google.cloud.vertexai.api.ModalityTokenCount>(
                  cacheTokensDetails_);
          bitField0_ |= 0x00000020;
        }
      }
<pre>
Output only. List of modalities that were processed in the request input.
</pre>

<code>
repeated .google.cloud.vertexai.v1.ModalityTokenCount prompt_tokens_details = 9 [(.google.api.field_behavior) = OUTPUT_ONLY];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/GenerateContentResponse.java