title: Emit items in RxJava in an interval which depends on the emitted item itself
body: <p>In RxJava for Android, I want to emit items in an interval which depends on the item itself: In the Observable, I pull an item from a queue, process it and emit it. Dependent on the type of the item, I want to adjust after what time the next item shall be emitted (slow down or speed up the interval).</p>
  
  <p>The following code, as proposed by @a.bertucci here <a href="https://stackoverflow.com/questions/26206805/emit-objects-for-drawing-in-the-ui-in-a-regular-interval-using-rxjava-on-android">Emit objects for drawing in the UI in a regular interval using RxJava on Android</a> demonstrates how to emit items in a regular interval.</p>
  
  <pre><code>private void drawPath(final String chars) {
      Observable.zip(
          Observable.create(new Observable.OnSubscribe&lt;Path&gt;() {
              // all the drawing stuff here
              ...
          }),
          Observable.timer(0, 50, TimeUnit.MILLISECONDS),
          new Func2&lt;Path, Long, Path&gt;() {
              @Override
              public Path call(Path path, Long aLong) {
                  return path;
              }
          }
      )
      .subscribeOn(Schedulers.newThread())
      .observeOn(AndroidSchedulers.mainThread())
      ...
  }
  </code></pre>
  
  <p>My question now is, if it is possible at all to modify the emission frequency while the observable is emitting, and what's the preferred implementation using RxJava.</p>