How to implement a simple lock in an asynchronous workflow

AsyncLock.cs

using System.Threading.Tasks;

namespace System.Threading
{
    public class AsyncLock : IDisposable
    {
        private readonly SemaphoreSlim semaphoreSlim = new SemaphoreSlim(1, 1);

        public async Task<AsyncLock> LockAsync()
        {
            await semaphoreSlim.WaitAsync();
            return this;
        }

        public void Dispose()
        {
            semaphoreSlim.Release();
        }
    }
}