Dart语言带有Break的标签

void main() { 
   outerloop: // This is the label name 
   for (var i = 0; i < 5; i++) { 
      print("Innerloop: ${i}"); 
      innerloop: 
      for (var j = 0; j < 5; j++) { 
         if (j > 3 ) break ; 
         // Quit the innermost loop 
         if (i == 2) break innerloop; 
         // Do the same thing 
         if (i == 4) break outerloop; 
         // Quit the outer loop 
         print("Innerloop: ${j}"); 
      } 
   } 
}