[Rust][DataFusion] Limit keeps polling input after limit is reached #28065
Description
Once the number of rows needed for a limit query has been produced, any further work done to read values from its input is wasted.
The current implementation of LimitStream will keep polling its input for the next value, and returning Poll::Ready(None) , even once the limit has been reached
This is wasteful
Reporter: Andrew Lamb / @alamb
Assignee: Andrew Lamb / @alamb
PRs and other links:
Note: This issue was originally created as ARROW-12254. Please see the migration documentation for further details.