can you refactor this to use modern c# code and avoid using locks? 
 private void ProcessQueue()
 {
 KeyValuePair req;

 while (canLoop)
 {
 if (queueRequest.TryPeek(out req))
 {
 canLoop = false;
 bool lockTaken = false;

 try
 {
 ////lock so can not come back in here a second time once its removed
 //// don't wait, if can't get lock then don't try
 Monitor.TryEnter(locker, 0, ref lockTaken);

 if (lockTaken)
 {
 bool cancel = false;

 if (cancelJobs.ContainsKey(req.Key))
 {
 cancel = true;
 cancelJobs.TryRemove(req.Key, out cancel);
 }

 if (!cancel)
 {
 ////there was an object in here so lets processs it
 GenCodeResponse response = this.GenerateCode(req.Value, req.Key);
 genCodeResults.TryAdd(req.Key, response);
 }

 ////we done so now remove it
 queueRequest.TryDequeue(out req);

 canLoop = true;
 }
 }
 finally
 {
 if (lockTaken)
 {
 Monitor.Exit(locker);
 }
 }
 }

 if (!queueProgress.Any())
 {
 cancelJobs.Clear();
 }

 this.requestWaitHandle.WaitOne();
 }
 }
user
you can use the `concurrentqueue` along with `async-await` to make a modern and lock-free implementation. here is the refactored code:

```csharp
using system.collections.concurrent;
using system.linq;
using system.threading;
using system.threading.tasks;

private readonly concurrentqueue<keyvaluepair> queuerequest = new concurrentqueue<keyvaluepair>();
private readonly concurrentdictionary<string, cancellationtokensource> canceljobs = new concurrentdictionary<string, cancellationtokensource>();
private readonly concurrentdictionary<string, gencoderesponse> gencoderesults = new concurrentdictionary<string, gencoderesponse>();
private cancellationtokensource globalcancellationtokensource = new cancellationtokensource();
private task queueprocessortask;

public void startprocessing()
{
    globalcancellationtokensource = new cancellationtokensource();
    queueprocessortask = task.run(processqueueasync, globalcancellationtokensource.token);
}

public void stopprocessing()
{
    globalcancellationtokensource.cancel();
    queueprocessortask.wait();
}

private async task processqueueasync()
{
    var cancellationtoken = globalcancellationtokensource.token;

    while (!cancellationtoken.iscancellationrequested)
    {
        if (queuerequest.trydequeue(out var req))
        {
            cancellationtokensource jobcancellationtokensource;

            if (canceljobs.tryremove(req.key, out jobcancellationtokensource))
            {
                jobcancellationtokensource.cancel();
            }

            if (jobcancellationtokensource == null || !jobcancellationtokensource.iscancellationrequested)
            {
                gencoderesponse response = await generatecodeasync(req.value, req.key, jobcancellationtokensource.token);
                gencoderesults.tryadd(req.key, response);
            }

            if (!queuerequest.any())
            {
                foreach (var k in canceljobs.keys)
                {
                    cancellationtokensource tmpcts;
                    canceljobs.tryremove(k, out tmpcts);
                    tmpcts?.dispose();
                }
            }
        }
        else
        {
            await task.delay(50, cancellationtoken);
        }
    }
}

// make generatecode async
private async task<gencoderesponse> generatecodeasync(object value, string key, cancellationtoken cancellationtoken)
{
    // your existing generatecode implementation goes here
    // change any blocking i/o call to async counterpart and use 'await'
    // ensure the cancellationtoken is passed to async methods

    // example:
    // var result = await longrunningmethodasync(cancellationtoken);
}
```

in this refactored code, there is no need for manual locks as the new `task.run()`, `async-await`, and `concurrentqueue` will manage the access to the shared resources. this example also includes handling cancellation using `cancellationtokensource`.
assistant
You can use the `ConcurrentQueue` along with `async-await` to make a modern and lock-free implementation. Here is the refactored code:

```csharp
using System.Collections.Concurrent;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

private readonly ConcurrentQueue<KeyValuePair> queueRequest = new ConcurrentQueue<KeyValuePair>();
private readonly ConcurrentDictionary<string, CancellationTokenSource> cancelJobs = new ConcurrentDictionary<string, CancellationTokenSource>();
private readonly ConcurrentDictionary<string, GenCodeResponse> genCodeResults = new ConcurrentDictionary<string, GenCodeResponse>();
private CancellationTokenSource globalCancellationTokenSource = new CancellationTokenSource();
private Task queueProcessorTask;

public void StartProcessing()
{
    globalCancellationTokenSource = new CancellationTokenSource();
    queueProcessorTask = Task.Run(ProcessQueueAsync, globalCancellationTokenSource.Token);
}

public void StopProcessing()
{
    globalCancellationTokenSource.Cancel();
    queueProcessorTask.Wait();
}

private async Task ProcessQueueAsync()
{
    var cancellationToken = globalCancellationTokenSource.Token;

    while (!cancellationToken.IsCancellationRequested)
    {
        if (queueRequest.TryDequeue(out var req))
        {
            CancellationTokenSource jobCancellationTokenSource;

            if (cancelJobs.TryRemove(req.Key, out jobCancellationTokenSource))
            {
                jobCancellationTokenSource.Cancel();
            }

            if (jobCancellationTokenSource == null || !jobCancellationTokenSource.IsCancellationRequested)
            {
                GenCodeResponse response = await GenerateCodeAsync(req.Value, req.Key, jobCancellationTokenSource.Token);
                genCodeResults.TryAdd(req.Key, response);
            }

            if (!queueRequest.Any())
            {
                foreach (var k in cancelJobs.Keys)
                {
                    CancellationTokenSource tmpCts;
                    cancelJobs.TryRemove(k, out tmpCts);
                    tmpCts?.Dispose();
                }
            }
        }
        else
        {
            await Task.Delay(50, cancellationToken);
        }
    }
}

// Make GenerateCode async
private async Task<GenCodeResponse> GenerateCodeAsync(object value, string key, CancellationToken cancellationToken)
{
    // Your existing GenerateCode implementation goes here
    // Change any blocking I/O call to async counterpart and use 'await'
    // Ensure the cancellationToken is passed to async methods

    // Example:
    // var result = await LongRunningMethodAsync(cancellationToken);
}
```

In this refactored code, there is no need for manual locks as the new `Task.Run()`, `async-await`, and `ConcurrentQueue` will manage the access to the shared resources. This example also includes handling cancellation using `CancellationTokenSource`.
assistant