/**
 * Loads the Velt script dynamically and calls the callback when ready.
 * Returns a cleanup function to remove the event listener if component unmounts.
 *
 * ## Issue (Rapid Mount/Unmount with Slow Network)
 *
 * When VeltProvider is rapidly mounted/unmounted (e.g., conditional rendering,
 * React Strict Mode, or route changes) while the Velt script is still loading
 * over a slow network, multiple issues can occur:
 *
 * 1. First component mount creates the script tag and starts loading
 * 2. Component unmounts before script loads (script tag remains in DOM)
 * 3. Second component mount finds existing script tag
 * 4. OLD BEHAVIOR: Immediately triggered callback assuming script was loaded
 * 5. PROBLEM: Script wasn't actually loaded yet (still loading due to network delay)
 * 6. This caused initVelt to run with window.Velt = undefined
 *
 * ## Fix
 *
 * 1. Check if window.Velt exists before triggering callback for existing scripts
 * 2. If script tag exists but window.Velt doesn't, attach a new load event listener
 * 3. Return a cleanup function that removes the event listener when component unmounts
 * 4. This prevents orphaned callbacks from firing on destroyed component instances
 *
 * @returns Cleanup function to remove event listener (call on component unmount)
 */
declare const loadVelt: (callback: Function, version?: string, staging?: boolean, develop?: boolean, proxyDomain?: string, integrity?: boolean, integrityValue?: string) => (() => void);
export default loadVelt;