Merge tag 'v4.1.0' into develop

Delegate unknown attrs to target in WrappingIO thanks to @william-andre. Added threaded progress bar example v4.1.0

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# gpg: Signature made Tue Oct 18 13:54:29 2022 CEST
# gpg:                using RSA key 149325FD15904E9C4EB89E95E81444E9CE1F695D
# gpg: Good signature from "Rick van Hattem <wolph@wol.ph>" [ultimate]
# gpg:                 aka "[jpeg image of size 9662]" [ultimate]

Author: wolph