title: When to use TaskCreationOptions.LongRunning?
body: <p>I've wondered this for quite a while, but never really found the answer. </p>
  
  <p>I understand that it's a hint for the task scheduler where the task will run on, and that the task scheduler can (or nowadays will?) decide to instantiate a non-thread-pool thread for that task.</p>
  
  <p>What I don't know (and surprisingly can't find nowhere on the internet) is some "rule of thumb" when to specify a task as long-running. Is one second long? 30 seconds? A minute? 5 minutes? Does it have a relation with the amount of tasks the application uses? Should I as programmer do some calculation with the #threads in the thread pool, how many Tasks I create, how many will be long-running at the same time, and based on that make a decision whether to use a long running task? </p>
  
  <p>Hope to learn something here.</p>