title: How to do proper Producer-Consumer pattern with RX
body: <p>How do I do producers-consumers with RX?</p>
  
  <p>I have found <a href="https://stackoverflow.com/questions/39768878/producer-consumer-with-rxjava">this</a> answer, it uses Java's scheduler that limits the number of concurent OnNext calls on the observer - so I could do something like that in C#, but I am sure that there is a another way to do that. Is there?</p>
  
  <p>Also, I found it weird that standard Subject does not wait for OnNext to end, it just fires immediately.</p>
  
  <p>Any thoughts?</p>