Can you narrate the story of Cholkar and his vow to Sai Baba as described in the texts?

The story of Cholkar, found in Chapter 15, is a touching account of a devotee's faith. Cholkar was 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. By Baba's grace, he passed the exam. However, due to financial hardships, described as the difficult 'threshold-ghat' of home expenses, he could not immediately fulfill his vow. As a personal penance for this delay, he gave up sugar entirely. When he finally reached Shirdi and fulfilled his vow, Baba revealed his omniscience by telling another devotee, Jog, to give Cholkar tea 'well-filled with sugar,' confirming that He knew about Cholkar's secret sacrifice all along.