Can you summarize the story of Cholkar, his vow, and the lesson he learned from Sai Baba?

The story of Cholkar, found in Chapter 15, illustrates the deep connection between a devotee and Sai Baba. Cholkar, a poor man, vowed to offer sugar candy in Shirdi if he passed a crucial job examination. After he succeeded, financial struggles delayed his journey, during which he gave up sugar himself. When he finally reached Shirdi and fulfilled his vow, Baba, in a remarkable display of omniscience, instructed that Cholkar be given tea that was "well-filled with sugar." This confirmed for Cholkar that Baba knew his secret vow and personal sacrifice. The experience culminated in Baba teaching him about His omnipresence and immanence in all beings.