迭代操作 meaning in English

iterated operation
iterative operation
repetitive operation

To store a list of listeners , as long as the list remains mutable and may be accessed by multiple threads , you must either lock the entire list during iteration or clone it before iteration , both of which have a significant cost
来存放一个侦听器列表，那么只要该列表是可变的，而且可能要被多个线程访问，您就必须要么在对其进行迭代操作期间，要么在迭代前进行的克隆操作期间，锁定整个列表，这两种做法的开销都很大。