Cancel/Abort request

[CesaTor]

Is your feature request related to a problem? Please describe.
I can't see any way to cancel or abort a request after it's sent

Describe the solution you'd like
I've seen in retrofit that it exists something like
@CancelRequest() CancelToken cancelToken
to allow the cancellation of a request.
I know this package uses http instead of dio but maybe there's a way to implement it too

Describe alternatives you've considered
I tried to cancel the Future in other ways or simply add a check to update the ui only if the response I get is the latest one using a scoped UniqueKey but it's pretty ugly and not that performant

Additional context
I'd really like to have something like that since I'm very happy with the package and find it very robust and consistent

[fryette]

It's impossible to cancel the request if it has already been sent.
You can read more about the Cancellation token to understand how it works. You can implement such logic by yourself.
Dio is useful but, at the same time, overloaded by such features.

[techouse]

Duplicate of #445

Blocked by dart-lang/http#424