C#: What is object pooling in .NET?

1builder.Services.AddObjectPoolBuilder()
2    .AddPipeline<MyObject>(policy =>
3    {
4        policy.MaximumRetained = 100;
5        policy.Factory = () => new MyObject();
6    });

1public class MyService(ObjectPool<StringBuilder> pool)
2{
3    public string Process(string input)
4    {
5        var sb = pool.Get();
6        try
7        {
8            sb.Append(input);
9            return sb.ToString();
10        }
11        finally
12        {
13            pool.Return(sb);
14        }
15    }
16}