code: function yep(data) {
            var err;
  
            if (data instanceof Error) err = data;
            if (!err && data) backup = collection.content = data;
            else collection.content = backup;
  
            self.logger.debug(
                'Received a'+ (err ? 'n error' : ' processed')
              + ' response from the '+ layer.id +' plugin '
              + (collection.length ? 'for a '+ collection.extension +' file' : '')
            );
  
            if (err) err.stack.split('\n').forEach(function print(line) {
              self.logger.error(line);
            });
  
            // Clean up before we continue
            layer.destroy();
            capture.dispose();
  
            processed = collection;
            done(err, processed);
          }
docs: Handle plugin responses from either a data, error or disregard emit.
  
  @param {String|Error} data
  @api private