async end() {
        log.debug(`Shutting down service registry client for ${this.identifier} of type ${this.serviceName}`);
        if (this.delay) {
            this.delay.cancel();
        }
    }
/**
     * shut down the client
     *
     * @return     {Promise}  undefined
     */
shut down the client
@return     {Promise}  undefined
shut down the client @return { Promise } undefined
async end() {
        log.debug(`Shutting down service registry client for ${this.identifier} of type ${this.serviceName}`);
        if (this.delay) {
            this.delay.cancel();
        }
    }
async end ( ) { log . debug ( ` ${ this . identifier } ${ this . serviceName } ` ) ; if ( this . delay ) { this . delay . cancel ( ) ; } }
shut down the client
 @return     {Promise}  undefined
shut down the client @return { Promise } undefined