Spot the bug: .NET

1using System.Collections.Generic;
2
3public class RequestCounter
4{
5    private readonly Dictionary<string, int> _counts = new();
6    private readonly object _lock = new();
7
8    public void Increment(string endpoint)
9    {
10        lock (_lock)
11        {
12            if (!_counts.ContainsKey(endpoint))
13                _counts[endpoint] = 0;
14            _counts[endpoint]++;
15        }
16    }
17
18    public int GetCount(string endpoint)
19    {
20        return _counts.TryGetValue(endpoint, out var count) ? count : 0;
21    }
22}