How does the author use foreshadowing in Double Indemnity?

Keyes is the head of the Claims Department. In Walter's first comments on Keyes, he pinpoints the man's character, "...the most tiresome man to do business with in the whole world. You can't even say today is Tuesday without he has to look on the calendar, and then check if it's this year's calendar or last year's calendar and then find out what company printed the calendar..." The name "Keyes" itself is blatantly symbolic of the role that he will play a "key" role in the story. The author foreshadows that role through Walter's one positive comment on Keyes's character: "...he's a wolf on a phony claim."