code: function getCollector() {
      var collector = new Collector();
  
      if (global['__coverage__']) {
          collector.add(global['__coverage__']);
      } else {
          console.error('No global coverage found for the node process');
      }
      return collector;
  }
docs: returns the coverage collector, creating one and automatically
  adding the contents of the global coverage object. You can use this method
  in an exit handler to get the accumulated coverage.