code: function(callback) {
              // We have to check "failOnFirst" flag to make sure we did not
              // throw the error before.
              if (phpcsError && !options.failOnFirst) {
                  this.emit('error', new gutil.PluginError(
                      'gulp-phpcs',
                      'PHP Code Sniffer failed on \n    ' + badFiles.join('\n    ')
                  ));
              }
  
              callback();
          }
docs: Abort if we had at least one error.