Provide a way to cancel client request.

We have ClientRequestContext.timeoutNow() to trigger timeout immediately. Similarly, it might be good to add ClientRequestContext.cancel() which cancels the current client request in case a user cannot easily cancel or abort the response such as https://github.com/line/centraldogma/blob/master/client/java/src/main/java/com/linecorp/centraldogma/internal/client/AbstractWatcher.java#L224

[minwoox]

If ctx is canceled after the request is fully sent (i.e waiting to get a response fully), the response is never canceled. So I think we should use a different approach.

Do you mean it should also use the TimeoutScheduler to schedule the cancellation?

I’m not sure if we can rename TimeoutScheduler to something else and generalize for this purpose (cancel or timeoutNow which just abort the response with the different exception), but it’s worth trying. What I meant was that we should do the same approach as TimeoutScheduler does. (It maintains the state of a request and cancel it if necessary.)

[minwoox]

Thanks, @tumile for your interest. I think it’s rather going to work exactly as ClientRequestContext.timeoutNow() does except raising CancellationException instead of ResponseTimeoutException. 😄