How exactly did Sai Baba reveal to Cholkar that He knew about his private vow regarding sugar?

In a powerful moment described in Chapter 15, Sai Baba revealed his omniscience to Cholkar in a very subtle yet direct way. After Cholkar had his darshan and fulfilled his vow by distributing sugar, he was a guest of a man named Jog. As Cholkar and Jog were about to leave, Baba, who did not drink tea himself, spoke to Jog and said, "Give him cups of tea, well-filled with sugar." Upon hearing these meaningful words, Cholkar was completely amazed, and tears of joy came to his eyes. He understood immediately that this was Baba's way of showing him that his secret vow and his personal penance of abstaining from sugar were fully known to Baba, which served to confirm his faith.