abstractmethod select(timeout=None)
Wait until some registered file objects become ready, or the timeout expires.
If timeout > 0, this specifies the maximum wait time, in seconds. If timeout <= 0, the call won’t block, and will report the currently ready file objects. If timeout is None, the call will block until a monitored file object becomes ready.
This returns a list of (key, events) tuples, one for each ready file object.
key is the SelectorKey instance corresponding to a ready fi