What was Cholkar's specific vow, and how did he uphold it before his visit to Shirdi?

Cholkar's vow to Sai Baba was to abstain from sugar until he could fulfill his pilgrimage and have Baba's darshan. According to Chapter 15, he was very strict in this observance, treating sugar as an "inedible substance." The text explicitly notes that he even drank his tea without sugar during this period. Despite a long delay before he could make the journey, Cholkar faithfully maintained this personal penance. His steadfastness was a secret he kept in his heart, which made Sai Baba's later acknowledgment of it all the more powerful and confirming for his faith.