getElapsedMs(startTimeNs) {
		const stopTimeNs = this.getTimeNs()
		const elapsedNs = stopTimeNs - startTimeNs
		return Number(elapsedNs / 1000000n)
	}
Calculates the elapsed time between the assigned start time and now in ms.
@param startTimeNs time in nanoseconds (bigint)
@return {Number} the elapsed time in milliseconds