try {
      const toString = Function.prototype.toString;
      const code = toString.call(fn);
      
      
      
      if (code.indexOf('^_^') > -1) {
        
        hasDetectedBadDCE = true;
        
        
        setTimeout(function() {
          throw new Error(
            'React is running in production mode, but dead code ' +
              'elimination has not been applied. Read how to correctly ' +
              'configure React for production: ' +
              'https:reactjs.org/link/perf-use-production-build',
          );
        });
      }
    } catch (err) {}
  }
  let uidCounter = 0;
  function inject(renderer) {