title: Why merged Fluxes do not interleave concurrently?
body: <p>I'm new to the Reactor, so I'd like to know, why is merging in this sample code working not as it's subscribed in the documentation. One flux returns odd numbers with a delay of 3 secs and other returns evens with a delay of 2 secs, but when I subscribe, it prints results of the first flux and then of the second one sequentially, but not interspersed. Return is 2, 4, 6, 8, .... 1, 3, 5, 7 etc, while I'm expecting 2, 4, 3, 6, 8, 5, 10, 7 etc. Other words: why don't two sourse fluces run in parallel?
  Here's a sample code</p>
  <pre><code>public class Main {
      public static void main(String[] args) throws InterruptedException {
          Flux.merge(fun1(10), fun2(10)).subscribe(System.out::println);
      }
  
      public static Flux&lt;Integer&gt; fun1(int i) {
          return Flux.range(1, i).map(integer -&gt; {
              try {
                  Thread.sleep(2000);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
              return integer * 2;
          });
      }
  
      public static Flux&lt;Integer&gt; fun2(int i) {
          return Flux.range(1, i).map(integer -&gt; {
              try {
                  Thread.sleep(3000);
              } catch (InterruptedException e) {
                  e.printStackTrace();
              }
              return integer * 2 + 1;
          });
      }
  }
  </code></pre>