Realize that comparing Clock.stamp to any value returned form Clock#tick is invalid as they are not done within the same mutex. This probably doesn’t affect anyone as this was only in a test, and the methods involved are all Internal.
After a `fork()` the node id in each child processes is still the same. Since the only other item that changes is the timestamp, then child processes could generate the same uuid if they originated in the same original parent process. This fixes #1 by detecting when the pid has changed and regenerating the node id at that point.