Check if master instance is slow and send an instance change request.
        :returns True if master performance is OK, False if performance
        degraded, None if the check was needed

def checkPerformance(self) -> Optional[bool]:
        """
        Check if master instance is slow and send an instance change request.
        :returns True if master performance is OK, False if performance
        degraded, None if the check was needed
        """
        logger.trace("{} checking its performance".format(self))

        # Move ahead only if the node has synchronized its state with other
        # nodes
        if not self.isParticipating:
            return

        if self.view_change_in_progress:
            return

        if not self._update_new_ordered_reqs_count():
            logger.trace("{} ordered no new requests".format(self))
            return

        if self.instances.masterId is not None:
            self.sendNodeRequestSpike()

            master_throughput, backup_throughput = self.monitor.getThroughputs(0)
            if master_throughput is not None:
                self.metrics.add_event(MetricsName.MONITOR_AVG_THROUGHPUT, master_throughput)
            if backup_throughput is not None:
                self.metrics.add_event(MetricsName.BACKUP_MONITOR_AVG_THROUGHPUT, backup_throughput)

            avg_lat_master, avg_lat_backup = self.monitor.getLatencies()
            if avg_lat_master:
                self.metrics.add_event(MetricsName.MONITOR_AVG_LATENCY, avg_lat_master)

            if avg_lat_backup:
                self.metrics.add_event(MetricsName.BACKUP_MONITOR_AVG_LATENCY, avg_lat_backup)

            degraded_backups = self.monitor.areBackupsDegraded()
            if degraded_backups:
                logger.display('{} backup instances performance degraded'.format(degraded_backups))
                self.backup_instance_faulty_processor.on_backup_degradation(degraded_backups)

            if self.monitor.isMasterDegraded():
                logger.display('{} master instance performance degraded'.format(self))
                self.view_changer.on_master_degradation()
                return False
            else:
                logger.trace("{}'s master has higher performance than backups".
                             format(self))
        return True