The first, fictional: In Part Two of Don Quixote, Cervantes tells of Grisostomo, an educated man who falls in love with a ravishing shepherd girl, and finally dies with a broken heart. At his funeral, Ambrosio, his educated friend, is about to set fire to Grisostomo's writings (he is said to have been a great poet and dramatist), and bystanders try to dissuade him from doing that, by reminding him of the second precedent: the pseudo-historical story of Virgil having ordered to burn the manuscript for the Aeneid because he did not have time to proof it. The emperor Augustus refused to comply.
And the obvious questions: How likely is it that Kafka was thinking of either story when he made out his will? How likely is it that Brod was? Are there other such precedents, literary or real?
P.S. Grisostomo's works are ultimately burnt, but Cervantes does treat us to a nice Petrarchan poem written by Grisostomo just before he died.