pkg_add is working very slow on NetBSD
Description of problem:
pkg_add is working very slow, it installs one package in ~30 minutes although network speed is normal.
Steps to reproduce:
1. `wget https://cdn.netbsd.org/pub/NetBSD/NetBSD-9.2/images/NetBSD-9.2-amd64.iso`
2. `qemu-img create -f qcow2 disk.qcow2 15G`
3. Install
```
qemu-system-x86_64 -m 2048 -enable-kvm \
  -drive if=virtio,file=disk.qcow2,format=qcow2 \
  -netdev user,id=mynet0,hostfwd=tcp::7722-:22 \
  -device e1000,netdev=mynet0 \
  -cdrom NetBSD-9.2-amd64.iso
```
       # Installation steps
       - 1) Boot Normally
       - a) Installation messages in English
       - a) unchanged
       - a) Install NetBSD to hard disk
       - b) Yes
       - a) 15G
       - a) GPT
       - a) This is the correct geometry
       - b) Use default partition sizes
       - x) Partition sizes are ok
       - b) Yes
       - a) Use BIOS console
       - b) Installation without X11
       - a) CD-ROM / DVD / install image media
       - Hit enter to continue
       - a) configure network (Select defaults here, perform autoconf)
       - x) Finished configuring
       - Hit enter to continue
       - x) Exit Install System
       - Close QEMU
4. Run
```
 qemu-system-x86_64 -m 2048 \
  -drive if=virtio,file=disk.qcow2,format=qcow2 \
  -enable-kvm  \
  -netdev user,id=mynet0,hostfwd=tcp:127.0.0.1:7722-:22 \
  -device e1000,netdev=mynet0
```
5. Login as root
6. In NetBSD
```
export PKG_PATH="http://cdn.NetBSD.org/pub/pkgsrc/packages/NetBSD/$(uname -p)/$(uname -r)/All/" && \
pkg_add pkgin

```
You should see that each of the package's installation takes ~30 minutes.
Additional information:
NetBSD 9.2 is also tested in Debian 11 with 'QEMU 6.2.0' and encountered same slowness. 

NetBSD 7.1 and 8.1 are tested on openSUSE Tumbleweed and encountered same slowness.

OpenBSD's pkg_add is working correctly.

I am not sure if it will help but Virtualbox(at least 6.1) is working correctly.