With signaling, something locally determined tells when your synchronized nodes need to stop or go, and makes them do that by sending a message.

This is what happens when your connection library starts a call-back after it connects; or blocks until the connection is ready; or use some continuation scheme, like futures to reorder your program and only start the next line of code after the connection is ready.

The alternative is what the article does. AFAIK, you can only do it in Javascript, because it's so obviously bad that no other language supports it.

For my example in circuitry, signal based synchronization uses a clock, or a ready signal. Time based synchronization just uses circuits that are ready to read data exactly when the previous step is done calculating it.