public CompletableFuture<T> execute(OAuth2Request oAuth2Request) {
        final HttpRequest request = oAuth2Request.asHttpRequest(endpointPath);
        final QueryParams requestParams = oAuth2Request.bodyParams();
        return endpoint.execute(request, UNARY_REQUEST_OPTIONS)
                       .aggregate()
                       .thenApply(response -> responseHandler.handle(response, requestParams));
    }
A simple wrapper around a WebClient that makes it easy to execute {@link OAuth2Request}s.
oauth2/src/main/java/com/linecorp/armeria/internal/common/auth/oauth2/OAuth2Endpoint.java