Causes this arbiters run() function to be executed in a newly spawned
        daemon process.

        Parameters
        ----------
        pgrpfile : str, optional
            Path at which to write a pgrpfile (file containing the process
            group id of the daemon process and its children).
        outfile : str, optional
            Path to text file to write stdout and stderr of workers to.
            (Daemonized arbiter process no longer has a stdout to write
            to.)  Defaults to "out.txt".

def spawn_daemon(self, pgrpfile=None, outfile="out.txt"):
        '''
        Causes this arbiters run() function to be executed in a newly spawned
        daemon process.

        Parameters
        ----------
        pgrpfile : str, optional
            Path at which to write a pgrpfile (file containing the process
            group id of the daemon process and its children).
        outfile : str, optional
            Path to text file to write stdout and stderr of workers to.
            (Daemonized arbiter process no longer has a stdout to write
            to.)  Defaults to "out.txt".
        '''
        if spawn_daemon(self.fork, pgrpfile, outfile):
            return
        signal.signal(signal.SIGTERM, lambda signal, frame: self.stop())
        self.run(False)