Called when the process has stopped.

        :param returncode: Process returncode

def _termination_callback(self, returncode):
        """
        Called when the process has stopped.

        :param returncode: Process returncode
        """

        if self.started:
            log.info("QEMU process has stopped, return code: %d", returncode)
            yield from self.stop()
            # A return code of 1 seem fine on Windows
            if returncode != 0 and (returncode != 1 or not sys.platform.startswith("win")):
                self.project.emit("log.error", {"message": "QEMU process has stopped, return code: {}\n{}".format(returncode, self.read_stdout())})