code: @Deprecated
      public CommandResult fsyncAndLock() {
          DBObject command = new BasicDBObject("fsync", 1);
          command.put("lock", 1);
          return getDB(ADMIN_DATABASE_NAME).command(command);
      }
docs: Forces the master server to fsync the RAM data to disk, then lock all writes. The database will be read-only after this command
  returns.
  
  @return result of the command execution
  @throws MongoException if there's a failure
  @mongodb.driver.manual reference/command/fsync/ fsync command