Method key_at

crates/aiur/src/querymap.rs:82–84

(&self, i: usize)

      assert!(p != libc::MAP_FAILED, "HugeVec mmap failed");
      // Advisory only: failure (old kernel, THP disabled) is harmless.
      libc::madvise(p, bytes, libc::MADV_HUGEPAGE);
      p.cast::<T>()
    };
    Self { ptr, cap, len: 0 }
  }