POE, AnyEvent, and IO::Async are three of the principle options in performing asynchronous operations in Perl.
We'll start off talking about appropriate use-cases for evented programming and the challenges of writing for asynchronous systems.
Evented systems tend to be chatty, so we'll also talk about messaging and conclude with some examples of how to implement a simple asynchronous task in the various architectures.
I promise not to mention "blockchain" in any way but ironically. Probably.