What is the origin story of the name 'Sai Baba' as described in the introductory chapter?

Chapter 0 explains the origin of the name 'Sai Baba.' When Maharaj first entered the Khandoba temple in Shirdi, he was wearing a kafni, a cap, and a dhoti. A devotee of Khandoba named Mhalasapati saw him and spontaneously welcomed him with the words 'Aavo Sai Baba,' which means 'Come, Sai Baba.' Maharaj held onto this name for the rest of his life. The text further mentions that when his testimony was taken in a commission and he was asked his name, he simply replied, 'They call me Sai Baba.'