Can you narrate the complete story of Cholkar's vow to Sai Baba and how it was fulfilled?

The story of Cholkar, as detailed in Chapter 15, begins with his vow to Sai Baba. Cholkar, who came from a poor household, needed to pass an examination to secure his job. He vowed that if he passed by Baba's grace, he would visit Shirdi and distribute sugar candy. He did pass, but due to financial difficulties, described as a 'threshold-ghat' that is hard for a worldly man to cross, he had to delay his trip. As a personal penance for this delay, he gave up eating sugar entirely. Eventually, he managed to travel to Shirdi, where he fulfilled his vow by distributing sugar. The climax occurred when Baba, who did not drink tea, instructed that Cholkar be given tea 'well-filled with sugar,' revealing His omniscience and confirming to Cholkar that his devotion and secret penance were known and accepted.