sub new {
    my $class = shift;
    my $self  = Excel::Writer::XLSX::Package::XMLwriter->new();

    ...
    $self->{_tempdir}            = undef;
    ...
}
sub _store_workbook {
    ...
    my $tempdir  = File::Temp->newdir( DIR => $self->{_tempdir} );
    ...
    $packager->_set_package_dir( $tempdir );
    $packager->_create_package();
    ...
}
sub set_tempdir {
    my $self = shift;
    my $dir  = shift;

    croak "$dir is not a valid directory" if defined $dir and not -d $dir;

    $self->{_tempdir} = $dir;
}