Architecture: socket.end() doesn't disconnect until I write something

I'm hoping to make a big push this month to make some good progress. Hopefully this will involve some well tested "Pull requests" from my clone of the "espruino/Espruino" project. However, I'm still somewhat new to GitHub and want to make sure I don't make a mistake. Here is what I have done so far.

1. I went to Github: espruino/Espruino and executed a "Fork" which created nkolban/Espruino.
   
2. I made small changes to this fork and issued a "Pull request" which was accepted.
   
   

Now ... weeks have passed and I want to make sure that the "nkolban/Espruino" is still in synch with the "espruino/Espruino". Is there a mechanism/recipe/technique I should use to make sure that my fork is up-todate with "espruino/Espruino"?