Return all files under a path

You are building a simple file crawler. ## Task Implement an API/function: - **Input:** a filesystem path `rootPath` - **Output:** a list/array of **all file paths** contained under `rootPath` (recursively), in any order. Assume: - Paths can be directories or files. - You are given a helper function similar to: - `listChildren(path) -> (subdirs, files)` where `subdirs` are immediate child directories and `files` are immediate child files. ## Notes / edge cases to clarify in your solution - If `rootPath` is a file, return just `[rootPath]`. - Decide what to do if the path does not exist or is not accessible (e.g., throw an error vs return empty). - Avoid infinite loops if the filesystem can contain symlinks (state your assumption if you ignore symlinks).