anchor.diff:  Now, we have an "infinite" number of lanes. The number of lanes grows to the point when we have
   enough lanes to handle all the arriving customers "just in time".
   
  -We output the numer of lanes / number of concurrently handled customers.
  +We output the numer of lanes (=number of concurrently handled customers).
   
   
  
positive.code: One could sum this up to:
  
  Rx is created mainly for "clients" (client applications like apps, desktop gui applications, ...) where
  you have typically one thread from the GUI and you would like to - on e.g. a form submit - "spin off" several background tasks (in parallel),
  combine those asynchronously returning results to one result which you display in the GUI.
  
  It's not primarly made for "servers", e.g. to handle concurrent HTTP requests in a webserver. But you can use it to do implement "servers", if you know "how".
  
negative.code: link:../src/main/java/ch/petikoch/examples/rxjava/threading/TwoLaneMcDrive.java[]
  
  Same as OneLaneMcDrive, but now with two lanes. There are still few customers arriving concurrently. Each of the lane
  is either free or there is maximum one customer in the lane. We have at each time between 0 and 2 customers concurrently.
  
  * Parallelism in a execution sense: We can handle two customers at the same time
  * Parallelism in a logical sense: like OneLaneMcDrive
  
  There is also no need for backpressure, since the customers arrive "slow " and the McDrive can handle them in time.
  
  