How did Sai Baba use a simple cup of tea to reveal his omniscience to Cholkar in Shirdi?

After Cholkar finally journeyed to Shirdi and fulfilled his vow by distributing sugar, he went to visit with a man named Jog. As Cholkar was about to leave, Sai Baba unexpectedly told Jog, "Give him cups of tea, well-filled with sugar." As Chapter 15 explains, this seemingly simple instruction was a profound revelation for Cholkar. Baba himself did not drink tea, so his specific mention of it, and particularly the instruction for it to be "well-filled with sugar," was a direct sign that he was aware of Cholkar's secret vow related to sugar and his personal penance of abstaining from it. This act amazed Cholkar, brought tears of joy to his eyes, and served to confirm his faith by proving Baba knew the hidden details of his devotion.