Function try_read_at_file 

pub(crate) fn try_read_at_file(
    handle: &Handle,
    ranges: &[(usize, usize)],
    dst: &mut Vec<u64>,
) -> Result<()>

Available on crate feature pager and Unix only.

Fallible counterpart to read_at_file. Returns Err instead of panicking on I/O failure (open/pread errors). Bounds violations and non-file handles still panic — those are caller bugs, not I/O failures.