code: public void reregisterExecutor(AppExecId appExecId, ExecutorShuffleInfo executorInfo) {
      blockManager.registerExecutor(appExecId.appId, appExecId.execId, executorInfo);
    }
docs: Register an (application, executor) with the given shuffle info.
  
  The "re-" is meant to highlight the intended use of this method -- when this service is
  restarted, this is used to restore the state of executors from before the restart.  Normal
  registration will happen via a message handled in receive()
  
  @param appExecId
  @param executorInfo