@Override
                        public FileVisitResult visitFile(final Path file,
                                                         final BasicFileAttributes attrs) {
                            deleteIfExists(file, success);
                            return super.visitFile(file, attrs);
                        }
@return True if path contains no files or directories.
@throws IOException if it is unable to list the contents of path
stroom-util/src/main/java/stroom/util/io/FileUtil.java