code: function forwardErrors(src, dst) {
    return src.on('error', function (err) {
      dst.emit('error', err, src);
    });
  }
docs: Forward any errors emitted on the source to the destination.
  
  @param src {EventEmitter} The initial source of error events.
  @param dst {EventEmitter} The new target of the source's error events. The
  original source will be provided as second argument (the error being the
  first).
  
  As a convenience, the source will be returned.