[arrow-cast] Unsupported output type for dictionary packing: FixedSizeBinary(16)

[metalmatze]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.

Currently, I get the following error:

Arrow error: Cast error: Unsupported output type for dictionary packing: FixedSizeBinary(16)

Describe the solution you'd like

I would like to be able to cast the type.
This is needed to group by in Datafusion.

Describe alternatives you've considered

Maybe first casting to utf8 or something, but that seems more like a work around in the query itself.

Additional context

A Datafusion query will throw the above error if the column foo has type FixedSizeBinary(16).

SELECT foo, count(bar) FROM table GROUP BY foo;