private static InstallPackage Copy(InstallPackage db)
{
var temp = Path.ChangeExtension(Path.GetTempFileName(), ".msi");
File.Copy(db.FilePath, temp, true);
// Open a copy and schedule delete it when closed.
var copy = new InstallPackage(temp, DatabaseOpenMode.ReadOnly);
copy.DeleteOnClose(temp);
return(copy);
}