interface changes slow to apply

[hescominsoon]

i've seen this for years in opnsense.  it doesn't matter if it's a xeon or an atom..interface changes can take between 10-30 seconds to apply.  I have noticed this on pfsense as well.  Is this a BSD thing?  There's not a linux firewall i've ever used that takes this long to apply interface changes.  Any BSD based firewall though takes this inordinate amount of time to apply interfaces changes.  I am curious what is going on to introduce this excessive and apparently endemic lag in interface change application.