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

The story of Cholkar, as narrated in Chapter 15, illustrates Sai Baba's omniscience. Cholkar, a man from a poor household, needed to pass an examination to make his job salary permanent. He made a firm resolve, vowing that if he passed by Baba's grace, he would visit Shirdi and distribute sugar candy. After passing the exam, he was unable to fulfill the vow immediately due to financial hardship, which the text calls the difficult "threshold-ghat" of home expenses. As a personal penance for the delay, Cholkar gave up sugar completely, even in his tea. When he was finally able to go to Shirdi, he had Baba's darshan, fulfilled his vow by distributing sugar, and his mind was filled with joy and supreme bliss.