Apply string trim to all fields including structs and arrays

[Matthew Ouyang]

I have a Row that has a struct that has string fields and an array of
structs which also has string fields.  Is there any simple way to apply a
whitespace trim to all string fields (like a ** wildcard)?  I know
FieldAccessDescriptor.withAllFields exists but will that work for anything
beyond the top level?  I'm hoping that I don't have to traverse the Row in
code.