What is the AddRange method in C# List?

List<int> list = new List<int>();
list.Add(100);
list.Add(200);
list.Add(300);
list.Add(400);

// array of 4 elements
int[] arr = new int[4];
arr[0] = 500;
arr[1] = 600;
arr[2] = 700;
arr[3] = 800;

list.AddRange(arr);

using System;
using System.Collections.Generic;

class Demo {
   static void Main() {
      List<int> list = new List<int>();
      list.Add(100);
      list.Add(200);
      list.Add(300);
      list.Add(400);

      // array of 4 elements
      int[] arr = new int[4];
      arr[0] = 500;
      arr[1] = 600;
      arr[2] = 700;
      arr[3] = 800;
   
      list.AddRange(arr);

      foreach (int val in list) {
         Console.WriteLine(val);
      }
   }
}