How did Sai Baba demonstrate His omniscience to Cholkar regarding the vow of sugar?

Sai Baba's demonstration of his omniscience to Cholkar was both subtle and profound, as recounted in Chapter 15. After Cholkar finally managed to visit Shirdi and distribute the sugar to fulfill his vow, he was a guest at Jog's place. As Cholkar was about to leave, Baba instructed Jog, 'Give him cups of tea, well-filled with sugar.' These meaningful words amazed Cholkar because only he knew the secret of his long penance of avoiding sugar. Baba later made this explicit, stating that the vow was accepted and his renunciation was complete, adding, 'Though you kept these secret, all of it is known to me.' This personal experience served to deeply confirm Cholkar's faith.