Increased latency after upgrade to .Net SDK 6.*

[jfreer]

I have an app that uses long-lived access tokens to upload files in the background.  In order to migrate to using refresh tokens, I upgraded from .Net SDK 4.9.* to .Net SDK 6.*.  The first call our app makes is to Files.GetMetadataAsync to determine if the file exists.  I noticed that if the call results in an AuthException (invalid_access_token), the latency of the call is now 10-20 seconds, whereas before the upgrade this was under 1 second.  I tried upgrading first to 6.0.1, and then to 6.2.  Same result.  There were 0 code changes with this upgrade; just an update of the Nuget package.  I have rolled back this upgrade until the problem is better understood.  I am using .Net core 3.1.  Any ideas why?

[jfreer]

I think I can answer my own question.  We create the DropboxClient without specifying MaxRetriesOnError.  In 6.*, this defaults to 4. If I set this to 0, then my code responds with latency values on par with the behavior in 4.9 SDK.  So, I suspect the 6.* SDK is retrying on AuthException, whereas the 4.9 SDK did not.  If it is retrying on AuthExceptions, this seems like a bug to me, especially if its an "invalid access token", as it is in my case.  The token isn't suddenly going to change and become valid on a retry.  

[Greg-DB]

Thanks! It looks like your understanding is correct. I'm bringing this up with the team to see if we can update the SDK to not retry on an auth failure like that.