"Vim’s event model
"Vim’s editing functions behave as if they are event-driven. For performance reasons, the actual implementation is more complex than that, with much of the event handling optimized away or handled several layers below the event loop itself, but you can still think of the editor as a simple while loop responding to a series of editing events.
"Whenever you start a Vim session, open a file, edit a buffer, change your editing mode, switch windows, or interact with the surrounding filesystem, you are effectively queuing an event that Vim immediately receives and handles.
"For example, if you start Vim, edit a file named demo.txt, swap into Insert mode, type in some text, save the file, and then exit, your Vim session receives a series of events like what is shown in Listing 1."
