writeRow(filename, headers, fields) {
		try {
			if (!fs.existsSync(filename))
				fs.writeFileSync(
					filename,
					headers.join(this.opts.delimiter) + this.opts.rowDelimiter
				);

			fs.appendFileSync(filename, fields.join(this.opts.delimiter) + this.opts.rowDelimiter);
		} catch (err) {
			/* istanbul ignore next */
			this.logger.error(
				`Unable to write metrics values to the '${filename}' file. Error: ${err.message}`,
				fields,
				err
			);
		}
	}
Write a row in CSV file
@param {String} filename
@param {Array<String>} fields