What Assange wants is not a decision from Sweden's
government, but a promise from Sweden's prosecutors [...].
The Swedish Prosecution Service has consistently refused
to promise that Assange wouldn't be extradited to the US
once in Swedish custody; this type of promise is common
in extradition cases and within the power of the Swedish
prosecution service
You're repeating the same assertion I questioned, verbatim. The author of this blog post quotes an article that itself quotes practically chapter and verse for why this type of promise is not feasible under Swedish law. I then said, if these promises were common, surely there's an example to be found of them somewhere.