/**
 * Throw a warning when a condition becomes true, but only once.
 *
 * This watches the condition function, and throws a warning when it returns true for the first
 * time. After that, it stops watching the condition, so that the warning is only thrown once.
 *
 * @param shouldWarn Condition to watch. When this returns true, the warning is thrown.
 * @param message Warning message
 */
export default function useWarnOnce(shouldWarn: () => boolean, message: string): void;