[C++] Add Future::DeferNotOk() #26200
Description
Provide a static method mapping Result<Future> -> Future. If the Result is an error, a finished future containing its Status will be constructed.
Reporter: Ben Kietzman / @bkietz
Assignee: Ben Kietzman / @bkietz
PRs and other links:
Note: This issue was originally created as ARROW-10196. Please see the migration documentation for further details.