SDK you're using (please complete the following information):

• Version Xero.NetStandard.OAuth2 9.2.0

Describe the bug
We have upgraded from Xero.NetStandard.OAuth2 6.0.0 to Xero.NetStandard.OAuth2 9.2.0
When uploading files to attach to an invoice we now get an error code 404, with error content "The resource you're looking for cannot be found"
If we remove the spaces from the filename the upload works correctly.
We have noticed that this error was introduced in Xero.NetStandard.OAuth2 9.0.0
The issue does not occur in 8.1.0.

To Reproduce
Upload a file with spaces.

Expected behavior
File attachment with spaces can be uploaded via .NET API.