header:  &Header{Xattrs: map[string]string{"用戶名": "\x00hello"}},
		paxHdrs: map[string]string{paxSchilyXattr + "用戶名": "\x00hello"},
		formats: FormatPAX,
	}, {
		header:  &Header{Xattrs: map[string]string{"foo=bar": "baz"}},
		formats: FormatUnknown,
	}, {
		header:  &Header{Xattrs: map[string]string{"foo": ""}},
		paxHdrs: map[string]string{paxSchilyXattr + "foo": ""},
		formats: FormatPAX,
	}, {