How does the author use foreshadowing in the novel, The You I’ve Never Known?

Over the course of the novel, Ariel receives a phone call from a woman who is drunk and asks for Casey. Ariel explains there is no Casey present. Later, Ariel recognizes Maya as the caller. The call foreshadows the arrival of the truth about Ariel’s past. Ariel is glad for the truth, but it turns her life upside down. It also causes her to question her limited amount of self-knowledge, which she was just beginning to piece together as a seventeen year-old.