MutexSlimCacheLock.cs

using System;
using System.Threading.Tasks;
using NHibernate.Cache;
using Pipelines.Sockets.Unofficial.Threading;

//Depends on nuget package: https://www.nuget.org/packages/Pipelines.Sockets.Unofficial
namespace YourNamespace
{
	public class MutexSlimCacheLock : ICacheLock
	{
		private readonly MutexSlim _mutexSlim;

		public MutexSlimCacheLock(int lockTimeoutMilliseconds)
		{
			_mutexSlim = new MutexSlim(lockTimeoutMilliseconds);
		}

		public void Dispose()
		{
		}

		public IDisposable ReadLock()
		{
			return CreateLock();
		}

		public IDisposable WriteLock()
		{
			return CreateLock();
		}

		public Task<IDisposable> WriteLockAsync()
		{
			return CreateAsyncLock();
		}

		public Task<IDisposable> ReadLockAsync()
		{
			return CreateAsyncLock();
		}

		private IDisposable CreateLock()
		{
			var lockToken = _mutexSlim.TryWait();
			if (lockToken)
				return lockToken;

			throw NewTimeoutException();
		}

		private async Task<IDisposable> CreateAsyncLock()
		{
			var lockToken = await _mutexSlim.TryWaitAsync().ConfigureAwait(false);

			if (lockToken)
				return lockToken;

			throw NewTimeoutException();
		}

		private static TimeoutException NewTimeoutException()
		{
			return new TimeoutException("Timeout obtaining lock.");
		}
	}

	public class MutexSlimCacheFactory : ICacheReadWriteLockFactory
	{
		public ICacheLock Create()
		{
			//TODO: provide your timeout here
			return new MutexSlimCacheLock((int) TimeSpan.FromMinutes(60).TotalMilliseconds);
		}
	}
}

SetUp.cs

Configuration cfg = ...
cfg.SetProperty(Environment.CacheReadWriteLockFactory, typeof(MutexSlimCacheFactory).AssemblyQualifiedName);