xml/>", "application/xml"); },
        {"Content-Type": ""},
        "",
        'XML Document request respects setRequestHeader("")'
      )
      request(
        function _XMLDocument() { return new DOMParser().parseFromString("<xml/>", "application/xml"); },
        {},
        "application/xml;charset=UTF-8",
        'XML Document request has correct default Content-Type of "application/xml;charset=UTF-8"'
      )
      request(
        function _XMLDocument() { return new DOMParser().parseFromString("