Why is the narrator asked to call on Simon Wheeler in "The Celebrated Frog of Calaveras County"?

Twain says he has a friend who asks Twain to ask Simon Wheeler to about a man named Leonidas W. Smiley. Twain says his friend was probably playing a joke on him and that Leonidas W. Smiley never existed. His friend wanted Twain to remind Wheeler of Jim Smiley so Wheeler would "bore me to death with some exasperating reminiscence of him." In other words, Twain's friend wanted Twain to hear the story of Jim Smiley and the jumping frog. Obviously, the friend was successful and Twain supposedly heard the story which he tells in "The Celebrated Jumping Frog of Calavaras County."