In chapter five in the beginning what is an example of foreshadowing when bilbo is alone in the tunnel

The discovery of the ring foreshadows something important..... and qualifies as a score for the company's thief!

"He guessed as well as he could, and crawled along for a good way, till suddenly his hand met what felt like a tiny ring of cold metal lying on the floor of the tunnel. It was a turning point in his career, but he did not know it."