Can you explain the story of Cholkar and how it demonstrates Sai Baba's omniscience?

The story of Cholkar, detailed in Chapter 15, illustrates Sai Baba's all-knowing nature. Cholkar, a man from a poor household, vowed that if he passed a crucial job examination, he would visit Shirdi and distribute sugar candy. He passed but was delayed in fulfilling the vow due to financial struggles, which the text calls the difficult "threshold-ghat." During this time, he gave up sugar completely, even in his tea. When he finally reached Shirdi and fulfilled his vow, Baba astonished him. As Cholkar was leaving with his host, Jog, Baba specifically instructed Jog to give Cholkar "cups of tea, well-filled with sugar." This act proved to Cholkar that Baba was aware of his secret vow and personal sacrifice, confirming that Baba knows everything a devotee does, no matter how far away they are.