Closes this QEMU VM.

def close(self):
        """
        Closes this QEMU VM.
        """

        if not (yield from super().close()):
            return False

        self.acpi_shutdown = False
        yield from self.stop()

        for adapter in self._ethernet_adapters:
            if adapter is not None:
                for nio in adapter.ports.values():
                    if nio and isinstance(nio, NIOUDP):
                        self.manager.port_manager.release_udp_port(nio.lport, self._project)

        for udp_tunnel in self._local_udp_tunnels.values():
            self.manager.port_manager.release_udp_port(udp_tunnel[0].lport, self._project)
            self.manager.port_manager.release_udp_port(udp_tunnel[1].lport, self._project)
        self._local_udp_tunnels = {}