public Map<String, byte[]> getXAttrs(Path path) throws IOException {
    return retrieveHeaders(path, INVOCATION_XATTR_GET_MAP);
  }
@Test
  public void testGetFilteredXAttrs() throws Throwable {
    Map<String, byte[]> xAttrs = headerProcessing.getXAttrs(MAGIC_PATH,
        Lists.list(XA_MAGIC_MARKER, XA_CONTENT_LENGTH, "unknown"));
    Assertions.assertThat(xAttrs.keySet())
        .describedAs("Attribute keys")
        .containsExactlyInAnyOrder(XA_MAGIC_MARKER, XA_CONTENT_LENGTH);
    // and the values are good
    assertLongAttributeValue(
        XA_MAGIC_MARKER,
        xAttrs.get(XA_MAGIC_MARKER),
        MAGIC_LEN);
    assertLongAttributeValue(
        XA_CONTENT_LENGTH,
        xAttrs.get(XA_CONTENT_LENGTH),
        FILE_LENGTH);
  }