async build(clientConfig, serverConfig) {
        this.clientConfig = clientConfig;
        this.serverConfig = serverConfig;

        if (this.isProd) {
            await this.buildProd();
        }
        else {
            await this.buildDev();
        }
    }
only called in SSR mode

@param {Object} clientConfig client webpack config
@param {Object} serverConfig server webpack config