This is the skeleton needed to implement classes that can be reused and
work together, which can perform asynchronous tasks (read: need to wait
for certain events before they can continue).
An example would be the task of waiting for a given inventory folder to
be read. This could then be used to improve the builtin AO
(automatically reading that folder when a notecard is dropped, and
continuing when the whole folder is read).
It's first use will be communication with a filepicker that runs
in a plugin.
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