This rewriting of the package is basically what I had in mind; the `_ep` was
just to signal a private package, which cannot be enforced, of course. Assuming
this rewriting would indeed avoid conflict with any standard protobuf package a
user might want to use, it would be nicer to do this using
Ah, I see. I guess that complicates things a little.
About the exposure part in C++, the idea is that if we statically link
libprotobuf and use private linkage for the generated classes, *hopefully*
users won't run into linking issues when they link to both Arrow and to
some libprotobuf of their o
