src/vs/base/common/scrollable.ts/SmoothScrollingOperation/_initAnimation
class SmoothScrollingOperation:	private _initAnimation(from: number, to: number, viewportSize: number): IAnimation {
		const delta = Math.abs(from - to);
		if (delta > 2.5 * viewportSize) {
			let stop1: number, stop2: number;
			if (from < to) {
				// scroll to 75% of the viewportSize
				stop1 = from + 0.75 * viewportSize;
				stop2 = to - 0.75 * viewportSize;
			} else {
				stop1 = from - 0.75 * viewportSize;
				stop2 = to + 0.75 * viewportSize;
			}
			return createComposed(createEaseOutCubic(from, stop1), createEaseOutCubic(stop2, to), 0.33);
		}
		return createEaseOutCubic(from, to);
	}