src/vs/workbench/services/extensions/common/extensionHostManager.ts/ExtensionHostManager/_measureLatency
class ExtensionHostManager:	private async _measureLatency(proxy: ExtHostExtensionServiceShape): Promise<number> {
		const COUNT = 10;

		let sum = 0;
		for (let i = 0; i < COUNT; i++) {
			const sw = StopWatch.create(true);
			await proxy.$test_latency(i);
			sw.stop();
			sum += sw.elapsed();
		}
		return (sum / COUNT);
	}