} else if (self.options.ssl.certStr && self.options.ssl.keyStr) {
        self.options.ssl.cert = self.options.ssl.certStr;
        self.options.ssl.key = self.options.ssl.keyStr;
    } else if (process.env.KAFKA_CLIENT_CERT_STR && process.env.KAFKA_CLIENT_CERT_KEY_STR) {
        self.options.ssl.cert = process.env.KAFKA_CLIENT_CERT_STR;