code: def task_index_by_rank(self, rank):
      resp = self._send(TaskIndexByRankRequest(rank))
      return resp.index
  
imports: import threading
  from horovod.runner.common.service import driver_service
  from horovod.runner.common.util import network
label_desc: Use image node_id 4 for calling the SparkDriverClient obj's underlying member method code with example usage: obj.task_index_by_rank(rank) and returns: resp