Closes an async-io-state and removes it from any internal structures.
A generalized boolean.
close-async-io-state also closes the object in async-io-state (that is, the argument to create-async-io-state). This closing can be prevented by supplying true for keep-alive-p, so you can perform further I/O operations on that object. In this case you will need to close object later.
async-io-state may contain some buffered data that it read from the object but did not use yet. The return value is the length of such data and you can use async-io-state-get-buffered-data to get it.
LispWorks User Guide and Reference Manual - 20 Sep 2017