Event loop or we can say it Message loop. in chromium it call message loop.

When main process run, chromium started infinity loop. running message direct never stop.

As we know javascript is single process. but they has lot of async event like http network event click & set time out function. async is way go for it.

When main process is blocking, user feel website not work status.

Different event type in different team, same event time only belong same team.