close

Closes these client options, relinquishing any underlying resources. This is purposefully not inherited from [AutoCloseable] because the client options are long-lived and usually should not be synchronously closed via try-with-resources. It's also usually not necessary to call this method at all. the default client automatically releases threads and connections if they remain idle, but if you are writing an application that needs to aggressively release unused resources, then you may call this method.