code: public RFuture<RedisClient> changeMaster(URI address) {
          ClientConnectionsEntry oldMaster = masterEntry;
          RFuture<RedisClient> future = setupMasterEntry(address);
          changeMaster(address, oldMaster, future);
          return future;
      }
docs: Freeze slave with <code>redis(s)://host:port</code> from slaves list.
  Re-attach pub/sub listeners from it to other slave.
  Shutdown old master client.
  
  @param address of Redis
  @return client