How do I get mwc-icon-button working with font awesome?

Question

I have the following...

<!-- Works -->
<i class="fab fa-linkedin" slot="actionItems"></i>
<!-- Does not work -->
<mwc-icon-button icon="linkedin" slot="actionItems"></mwc-icon-button>

Also tried variations like...

<mwc-icon-button icon="fa-linkedin" slot="actionItems"></mwc-icon-button>
<mwc-icon-button class="fab fa-linkedin" icon="linkedin" slot="actionItems"></mwc-icon-button>

But can't get it so what is the deal?