Is there a way to overwrite existing cache belongs to a context in Polly cache?

Summary: What are you wanting to achieve? I am new to Polly and I am using Polly to save response from API call. I am using .net standard library project. I am able to save cache. But I need to overwrite cache item after any update occurred to that resource.

What code or approach do you have so far?
This is how I configured for polly caching.

services.AddMemoryCache();
			services.AddSingleton<IAsyncCacheProvider, MemoryCacheProvider>();
			services.AddSingleton<IReadOnlyPolicyRegistry<string>, Polly.Registry.PolicyRegistry>((serviceProvider) =>
			{
				var registry = new PolicyRegistry();
				registry.Add("exchangeCachePolicy",
					Policy.CacheAsync(
						serviceProvider
							.GetRequiredService<IAsyncCacheProvider>()
							.AsyncFor<List<OutlookCategory>>(),
						new SlidingTtl(TimeSpan.FromMinutes(5))));
				return registry;
			});

I used following code to read from cache

var existingMasterCategories =  await _policyRegistry.Get<IAsyncPolicy<List<OutlookCategory>>>("exchangeCachePolicy")
													.ExecuteAsync(async context => await GetMasterCategoriesAsync(exchangeUserId), new Context($"GetOutlookMasterCategories-{exchangeUserId}"));

It is always useful to see:

• code of any policy declarations,
• code of the calls to .Execute/AndCapture/Async(...)

[piyumi25]

var messageWithCategory = new Message();
var outlookCategoryColor = (CategoryColor)Enum.Parse(typeof(CategoryColor), categoryColor);

// check for master categories in polly cache and get it, else call GetMasterCategoriesAsync()
var existingMasterCategories =  await _policyRegistry.Get<IAsyncPolicy<List<OutlookCategory>>>("exchangeCachePolicy")
	.ExecuteAsync(async context => await GetMasterCategoriesAsync(exchangeUserId), new Context($"GetOutlookMasterCategories-{exchangeUserId}"));

var a3SyncCategory = existingMasterCategories.FirstOrDefault(x => x.DisplayName.Equals(categoryName, StringComparison.InvariantCultureIgnoreCase));
				
if (a3SyncCategory == null)
{
	// create master category
	a3SyncCategory = await CreateMasterCategoryAsync(exchangeUserId, categoryName, outlookCategoryColor);
	//update cache
}
else
{
	//check if category has same color
	if (!a3SyncCategory.Color.Value.Equals(outlookCategoryColor))
	{
		//update category color
		a3SyncCategory = await UpdateMasterCategoryAsync(exchangeUserId,a3SyncCategory.Id, categoryName, outlookCategoryColor);
		//update cache
		var cancellationToken = new CancellationToken();
		var updatedMasterCategories = await GetMasterCategoriesAsync(exchangeUserId);
		await _cacheProvider.PutAsync(
			"exchangeCachePolicy",
			updatedMasterCategories,
			new Ttl(TimeSpan.FromMinutes(5)),
			cancellationToken,
			true);
	}
}

@martincostello Above is the part of the method I am using to integrate with polly cache

[martincostello] Edited formatting for readability

[piyumi25]

Thanks @martincostello , I will try for this.