src/vs/platform/log/node/spdlogLog.ts/SpdLogLogger/_createSpdLogLogger
class SpdLogLogger:	private _createSpdLogLogger(): Promise<void> {
		const filecount = this.rotating ? 6 : 1;
		const filesize = (30 / filecount) * ByteSize.MB;
		return createSpdLogLogger(this.name, this.filepath, filesize, filecount)
			.then(logger => {
				if (logger) {
					this._logger = logger;
					this._logger.setLevel(this.getLevel());
					for (const { level, message } of this.buffer) {
						log(this._logger, level, message);
					}
					this.buffer = [];
				}
			});
	}