Commits
Benjamin Kietzman authored and Antoine Pitrou committed 218cb5ec13d
ARROW-7091: [C++] Move DataType factory decls to type_fwd.h This also necessitated moving UnionMode and TimeUnit Closes #6689 from bkietz/7091-Move-all-factories-to-typ Authored-by: Benjamin Kietzman <bengilgit@gmail.com> Signed-off-by: Antoine Pitrou <antoine@python.org>