Can you describe the specific incident at Shirdi that proved to Cholkar that Sai Baba was omniscient?

The moment that confirmed Baba's omniscience for Cholkar occurred after he had already fulfilled his vow. According to Chapter 15, Cholkar had his darshan, distributed sugar, and was staying as a guest of Jog. As Cholkar and Jog were about to leave, Sai Baba told Jog, "Give him cups of tea, well-filled with sugar." This specific instruction amazed Cholkar because Baba did not drink tea, and no one else knew about Cholkar's secret, personal vow to abstain from sugar until he could visit Shirdi. Hearing these meaningful words, Cholkar was overcome with emotion, and tears of joy came to his eyes as he realized Baba knew his innermost secrets.