t with set type keeps setRequestHeader() Content-Type and charset"
      )
      request(
        function _ArrayBuffer() { return new ArrayBuffer(10); },
        {"Content-Type": ""},
        "",
        'ArrayBuffer request respects setRequestHeader("")'
      )
      request(
        function _ArrayBuffer() { return new ArrayBuffer(10); },
        {},
        undefined,
        "ArrayBuffer request sends no Content-Type without setRequestHeader() call"
      )
      request(
        function _ArrayBuffer