Function pageout_with 

pub fn pageout_with(b: Backend, chunks: &mut [Vec<u64>]) -> Handle

Available on crate feature pager and Unix only.

Same as pageout, but selects the backend explicitly. Bypasses the global atomic so callers (such as the column-pager layer) can dispatch per call without racing other writers.

Panics on I/O failure. Use try_pageout_with to surface the error.