(very internal) refill the repeat buffer

def _rebuffer(self):
        """
        (very internal) refill the repeat buffer
        """
        results = []
        exceptions = []
        for i in xrange(self.stride):
            try:
                results.append(self.iterable.next())
                exceptions.append(False)
            except Exception, excp:
                results.append(excp)
                exceptions.append(True)
        self._repeat_buffer = repeat((results, exceptions), self.n)