def sendUpdate(self, data):
        """This sends the status update to the master-side
        L{buildbot.process.step.RemoteCommand} object, giving it a sequence
        number in the process. It adds the update to a queue, and asks the
        master to acknowledge the update so it can be removed from that
        queue."""

        if not self.running:
            # .running comes from service.Service, and says whether the
            # service is running or not. If we aren't running, don't send any
            # status messages.
            return
        # the update[1]=0 comes from the leftover 'updateNum', which the
        # master still expects to receive. Provide it to avoid significant
        # interoperability issues between new workers and old masters.
        if self.remoteStep:
            update = [data, 0]
            updates = [update]
            d = self.remoteStep.callRemote("update", updates)
            d.addCallback(self.ackUpdate)
            d.addErrback(self._ackFailed, "WorkerForBuilder.sendUpdate")