Returns an identifier string of this instance. Defaults to the name of the class, but may be overridden if more detailed information is required.
Returns true if the client's file handle is registered with epoll for the events specified with the client reference as attachment. Returns false if the client's file handle is not registered with epoll or, when multiple instances of the implementing class share the same file handle, if it is registered with another instance.
Returns a string describing this client, for use in debug messages.