What are examples of foreshadowing in the short story, "Through the Tunnel" by Doris Lessing?

Several instances of foreshadowing, or hints of what is to come, occur in the exposition of Doris Lessing's "Through the Tunnel."

The story opens as Jerry follows his mother to the beach. In the first instance of foreshadowing, they walk to the customary beach, but Jerry, who is behind his mother, glances out at the wild bay. His mother notices his look of longing and asks him about it in another instance of foreshadowing,

“Why, darling, would you rather not come with me? Would you rather—” She frowned, conscientiously worrying over what amusements he might secretly be longing for, which she had been too busy or too careless to imagine.

Jerry's mother senses that her son wants to venture off from her, and she worries that maybe he wants to become more independent. In a further instance of foreshadowing, on the following day, Jerry tells his mother that he wishes to go to the wild bay and examine the rocks. So, she realizes that her anxieties about his wishing to be more independent were real.

These actions and desires of Jerry, along with his mother's anxieties about treating him too much like a child indicate that Jerry is at a point in his life in which he will soon make the transition from boy to teenager. The mother, also, wants to keep herself from being too protective so that Jerry is able make this transition to being more independent. Thus, these actions and conversations foreshadow Jerry's swimming successfully through the rock's tunnel, completing his rite of passage into young adulthood.