Awaiting on Monitor lock vs. AsyncEx

Program.cs

using System;
using System.IO;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Nito.AsyncEx;

namespace ConsoleApp4
{
    public static class Program
    {
        private static readonly object monitorLockTarget = new object();

#if false
        private static async Task InvalidAwaitingUsage()
        {
            lock (monitorLockTarget)
            {
                using (var fs = new FileStream("nyaruko.txt", FileMode.Create, FileAccess.ReadWrite, FileShare.None, 65536, true))
                {
                    var tw = new StreamWriter(fs, Encoding.UTF8);

                    // error CS1996: Cannot await in the body of a lock statement
                    await tw.WriteLineAsync("She has a likely bar.");
                    await tw.FlushAsync();
                }
            }
        }
#endif
        private static async Task DangerousForceAwaitingUsage()
        {
            Monitor.Enter(monitorLockTarget);
            try
            {
                using (var fs = new FileStream("nyaruko.txt", FileMode.Create, FileAccess.ReadWrite, FileShare.None, 65536, true))
                {
                    var tw = new StreamWriter(fs, Encoding.UTF8);

                    await tw.WriteLineAsync("She has a likely bar.");
                    await tw.FlushAsync();
                }
            }
            finally
            {
                Monitor.Exit(monitorLockTarget);
            }
        }

        private static readonly AsyncLock asyncLockTarget = new AsyncLock();

        private static async Task ValidAwaitingUsage()
        {
            using (await asyncLockTarget.LockAsync())
            {
                using (var fs = new FileStream("nyaruko.txt", FileMode.Create, FileAccess.ReadWrite, FileShare.None, 65536, true))
                {
                    var tw = new StreamWriter(fs, Encoding.UTF8);

                    // Can do it.
                    await tw.WriteLineAsync("She has a likely bar.");
                    await tw.FlushAsync();
                }
            }
        }

        static async Task Main(string[] args)
        {
            // System.Threading.SynchronizationLockException: 'Object synchronization method was called from an unsynchronized block of code.'
            await DangerousForceAwaitingUsage();

            await ValidAwaitingUsage();
        }
    }
}