Get current network limit for subflows.

def _GetSubFlowNetworkLimit(self):
    """Get current network limit for subflows."""

    subflow_network_limit = None

    if self.runner_args.per_client_network_limit_bytes:
      subflow_network_limit = self.runner_args.per_client_network_limit_bytes

    if self.runner_args.network_bytes_limit:
      remaining_network_quota = (
          self.runner_args.network_bytes_limit -
          self.context.network_bytes_sent)
      if subflow_network_limit is None:
        subflow_network_limit = remaining_network_quota
      else:
        subflow_network_limit = min(subflow_network_limit,
                                    remaining_network_quota)

    return subflow_network_limit