anchor.diff:  * class loading related statistics
   * thread count information (current, peak and daemon thread counts)
   
  +[[cluster-metrics]]
   === Jet Cluster metrics ===
   
   [cols="3,2"]
  
positive.code: `Metric` instance outside of the block executing on the ForkJoinPool, it
  also creates a "thread-safe" type of metric.
  
  === Exposing metrics ===
  
  The main method Jet has for exposing the metrics to the outside world is
  
negative.code: their name implies: they are not built-in, but defined when processing
  pipelines are written.
  
  Since user metrics are also job metrics, they will have all the tags
  job metrics have. They also have an extra tag, called `USER` which is
  of type `boolean` and is set to `true`.
  
  Let's see how one would go about defining user metrics. For example if
  you would like to monitor your filtering step you could write code like
  