Can you walk me through the entire story of Cholkar, including the vow he made and how Sai Baba demonstrated his omniscience?

The story of Cholkar, as detailed in Chapter 15, begins with him being a poor man who needed to pass an examination to secure his job. He made a vow to Sai Baba that if he passed, he would come to Shirdi and distribute sugar candy. Although his wish was granted, he faced financial difficulties, described as the hard-to-cross "threshold-ghat," which delayed his journey. As a personal penance for this delay, he gave up sugar completely. When he finally arrived in Shirdi and fulfilled his vow, Baba, who was aware of Cholkar's secret sacrifice, instructed a devotee named Jog to serve Cholkar tea that was "well-filled with sugar." This act amazed Cholkar, proving that Baba knew his innermost thoughts and actions.