[C++][Dataset] Dataset should instantiate Fragment

[asfimport]

Fragments are created on the fly when invoking a Scan. This means that a lot of the auxilliary/ancilliary data must be stored by the specialised Dataset, e.g. the FileSystemDataset must hold the path and partition expression. With the venue of more complex Fragment, e.g. ParquetFileFragment, more data must be stored.

Reporter: Francois Saint-Jacques / @fsaintjacques
Assignee: Francois Saint-Jacques / @fsaintjacques

Related issues:

• [C++][Dataset] Untangle Dataset, Fragment and ScanOptions (is blocked by)

PRs and other links:

• GitHub Pull Request #7073

_{Note: This issue was originally created as ARROW-8318. Please see the migration documentation for further details.}

[asfimport]

Ben Kietzman / @bkietz:
Issue resolved by pull request 7073
#7073