@NotNull
    public static FileInfo empty() {
        return EMPTY_FILE_INFO;
    }
@Test
    public void empty() {
        assertThat(FileInfo.empty()).isEqualTo(FileInfo.builder()
                .path(Paths.get(""))
                .key(null)
                .modificationTime(null)
                .size(-1L)
                .build());
    }