Distinguish connection or server error during client.Exchange()

[ilkondr]

Hi there!

Is there a way to check error type to distinguish connection/server error from packet encoding error?
I need to walk thru the list of Radius servers and now it's not clear if I need to try next server or stop.

Thanks

There is not a great solution for this right now. Ideally, each type of error that this library would return would have its own specific error type that could be used in conjunction with errors.Is.

[jamiesun]

Opened #142 to address this. Thanks @ilkondr for the report — it adds a typed MalformedRequestError (with Unwrap) so callers can use errors.As to tell an un-encodable request apart from a network/server error and make failover decisions accordingly.