For some reason, suddenly, IPv6 on my Windows 2008 R2 system stopped working.I wasn't able to ping or trace route with the following commands: ping -6 www.google.com tracert -6 www.google.comWhen I used route -6 delete * to delete the routing table, followed by disabling and re-enabling IPv6 protocol on the adapter, it worked for a while, and then stopped.Eventually, I figured out there were stale entries in the IP configuration, and a simple ipconfig /release6 * resolved it. I was then able to ping and trace route on IPv6 to www.google.com.
It seems that Windows had a bug with regards to IPv6.
In 2017, with the release of Delphi 10.2 Tokyo, Embarcadero introduced a specialized implementation of the Observer pattern into the System.Classes unit. While it has been in the wild for 9 years, it remains a "hidden" architecture for many, primarily because it serves as the invisible engine behind LiveBindings. Other than live bindings, you can also use the Observer pattern as a way to update component settings to the Windows registry, an .ini file, or persist it elsewhere.
System.Classes