E reduce (E combine(E previousValue, E element)) inherited
E reduce(E combine(E previousValue, E element)) { int length = this.length; if (length == 0) throw IterableElementError.noElement(); E value = this[0]; for (int i = 1; i < length; i++) { value = combine(value, this[i]); if (length != this.length) { throw ConcurrentModificationError(this); } } return value; }