code: def mark_broker_action_done(action, rid=None, unit=None):
      
      rdata = relation_get(rid, unit) or {}
      broker_rsp = rdata.get(get_broker_rsp_key())
      if not broker_rsp:
          return
  
      rsp = CephBrokerRsp(broker_rsp)
      unit_name = local_unit().partition('/')[2]
      key = "unit_{}_ceph_broker_action.{}".format(unit_name, action)
      kvstore = kv()
      kvstore.set(key=key, value=rsp.request_id)
      kvstore.flush()
docs: Mark action as having been completed.
  
      @param action: name of action to be performed
      @returns None