docs: public static void copyFile(@NotNull Path from, @NotNull Path to) throws IOException {
  		Validate.isTrue(Files.exists(from), "%s is not exist or not a file", from);
  		Validate.notNull(to);
  		Validate.isTrue(!FileUtil.isDirExists(to), "%s is exist but it is a dir", to);
  		Files.copy(from, to);
  	}