src/vs/workbench/contrib/output/common/outputChannelModel.ts/OutputFileListener/doWatch
class OutputFileListener:	private doWatch(): Promise<void> {
		return this.fileService.resolve(this.file, { resolveMetadata: true })
			.then(stat => {
				if (stat.etag !== this.etag) {
					this.etag = stat.etag;
					this._onDidContentChange.fire(stat.size);
				}
			});
	}