public Builder setApiKeyConfig(com.google.cloud.vertexai.api.ApiAuth.ApiKeyConfig value) {
      if (apiKeyConfigBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        authConfig_ = value;
        onChanged();
      } else {
        apiKeyConfigBuilder_.setMessage(value);
      }
      authConfigCase_ = 1;
      return this;
    }
<pre>
The API secret.
</pre>

<code>.google.cloud.vertexai.v1.ApiAuth.ApiKeyConfig api_key_config = 1;</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ApiAuth.java