How does the author use foreshadowing in Angels in America?

Part I: Act II, Scene VI, the choice Joe faces becomes a choice between idealism and reality. In the Reaganite society, friendships have one important requirement.... they need to be useful. Thus, the choice Joe faces now foreshadows a later, more essential choice he will have to make between being what he knows he is (homosexual), and what he feels obliged to be.