title: What is the Meteor concurrency model?
body: <p>I'm writing server-side logic for a Meteor app that has to update in-memory state in response to requests from the client. This application needs strong concurrency guarantees - in particular, I want to be sure that there is only one update executed at a time.</p>
  
  <p>I'm trying to figure out if Meteor's concurrency model supports this. The documentation mentions that Meteor is multithreaded (which would be a problem), but after searching around, I get the impression that Meteor is actually uses fibers (explicitly scheduled threads). If that's true, then I'm safe as long as the part of my code that needs to run atomically doesn't make any Meteor calls (which involve IO and thus yield the execution lock).</p>
  
  <p>Is this the case? Where can I find more information on Meteor's concurrency model? </p>