How does the author use foreshadowing in Joe Turner's Come and Gone?

In Act II, Scene III, Bynum's and Bertha's advice to Mattie about waiting for her good fortune is a form of foreshadowing which has almost immediate consequences. Bertha advises Mattie to be patient and then her future will one day appear in front of her. As if on cue, Herald enters the room and he and Mattie share their own personal disappointments, which draws the two of them together. Herald needs some further personal development and some more self confidence in order to proceed with the relationship, but the groundwork is laid, bringing Bynum's and Bertha's advice full circle.