}

        public ToolchainsBuilderRequest build() {
            return new ToolchainsBuilderRequestBuilder.DefaultToolchainsBuilderRequest(
                    session, installationToolchainsSource, userToolchainsSource);
        }

        private static class DefaultToolchainsBuilderRequest extends BaseRequest implements ToolchainsBuilderRequest {
            private final Source installationToolchainsSource;