What’s the Origin of the Boston Cooler?

“I moved from Washington, D.C. to Detroit in the mid-’90. And I’ve always loved the root beer float and people said, ‘You have to try the Boston Cooler.’ So, I tried it and was like, ‘What’s the deal here? Why’s it called a Boston Cooler and not a ginger ale cooler or something like that? I’m just curious.”