[C++] Improve the performance of Tensor-to-SparseTensor conversion #25416
Description
In ARROW-9156, I rewrote Tensor-to-SparseTensor converters to reduce the library size. There was a drawback of that change, that is slowing down the conversion. We need additional change to improve conversion speed.
Reporter: Kenta Murata / @mrkn
Assignee: Kenta Murata / @mrkn
PRs and other links:
Note: This issue was originally created as ARROW-9331. Please see the migration documentation for further details.