internal static extern uint MsiEnableLog(NativeMethods.LogMode dwLogMode, [MarshalAs(UnmanagedType.LPWStr)] string szLogFile, uint dwLogAttributes);
internal static extern MyMsiInstallUIHandler MsiSetExternalUI([MarshalAs(UnmanagedType.FunctionPtr)] MyMsiInstallUIHandler puiHandler, NativeMethods.LogMode dwMessageFilter, IntPtr pvContext);