/**
 * Throttles a function using requestAnimationFrame with optional frame skipping.
 * Ensures the function runs at most once per N-frames.
 * - frameSkip = 0 → run every frame
 * - frameSkip = 1 → run every 2nd frame
 * - frameSkip = 2 → run every 3rd frame, etc.
 *
 * @param {Function} fn - Function to throttle
 * @param {number} [frameSkip=0] - Number of frames to skip between calls
 * @returns {Function} throttled function
 */
export function throttleRaf(fn: Function, frameSkip?: number): Function;