Creates a conditional lock based on given boolean and a key. Threads with same key will be locked.

SharedConditionalLock.cs

public class SharedConditionalLock : IDisposable
{
    private static readonly ConcurrentDictionary<string, object> _locks = new ConcurrentDictionary<string, object>();

    public SharedConditionalLock(string key, bool isEnabled)
    {
        Key = key;
        IsEnabled = isEnabled;

        if (isEnabled)
        {
            Monitor.Enter(_locks.GetOrAdd(Key, new object()));
        }
    }

    public bool IsEnabled { get; }

    public string Key { get; }

    public void Dispose()
    {
        if (IsEnabled)
        {
            Monitor.Exit(_locks[Key]);
        }
    }
}