Adding CancellationToken to context.Items to subscribe

[hdrachmann]

We see a problem where Azure Service bus is never going to accept the renewal request for the locks - which results in a state where the message is never going to be completed by the handler.
This is a transient error - so instead we want to be able to fail fast.
This is done by adding a CancellationToken that can be listened to in the Handler to see whether to stop the handling of the message by throwing a OperationCancelException

token.ThrowIfCancellationIsRequested()

Enhancements to message lock renewal and cancellation:

• Added a new ConcurrentDictionary named _messageRenewerTokenSources to store CancellationTokenSource objects for each message to manage cancellation tokens during lock renewal. (AzureServiceBusTransport.cs, Rebus.AzureServiceBus/AzureServiceBus/AzureServiceBusTransport.csR64)
• Updated the Receive method to create and store a linked CancellationTokenSource for each message, which combines the pipeline cancellation token with a token that cancels if lock renewal fails. The token is added to the transaction context for use during message processing. (AzureServiceBusTransport.cs, Rebus.AzureServiceBus/AzureServiceBus/AzureServiceBusTransport.csL621-R628)
• Ensured proper cleanup of cancellation tokens by removing and disposing of them in the OnAck, OnNack, and OnDisposed callbacks of the transaction context. (AzureServiceBusTransport.cs, [1] [2] [3]
• Modified the lock renewal logic to cancel the associated token when a peek lock renewal fails, allowing dependent processes to respond appropriately. (AzureServiceBusTransport.cs, Rebus.AzureServiceBus/AzureServiceBus/AzureServiceBusTransport.csL968-R985)

[Copilot]

Pull Request Overview

This PR adds tracking and cancellation of message lock renewal tokens in the Azure Service Bus transport to ensure that renewal tasks can be stopped when a message is completed, abandoned, or an error occurs.

• Introduces a _messageRenewerTokenSources dictionary to hold CancellationTokenSource instances per message.
• Creates a linked cancellation token source in Receive and stores it in the context items.
• Hooks into the OnAck, OnNack, and OnDisposed callbacks to remove token sources, and cancels them when renew failures occur.

Comments suppressed due to low confidence (1)

Rebus.AzureServiceBus/AzureServiceBus/AzureServiceBusTransport.cs:620

• [nitpick] Consider renaming renewFailedTokenSource to something like renewalTokenSource or messageRenewalTokenSource for clarity.

        var renewFailedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, _cancellationToken);