code: func (impl *adminImpl) LaunchJob(c context.Context, cfg *api.JobConfig) (*api.JobID, error) {
  	def, ok := mappers[cfg.Kind] // see mappers.go
  	if !ok {
  		return nil, status.Errorf(codes.InvalidArgument, "unknown mapper kind")
  	}
  
  	cfgBlob, err := proto.Marshal(cfg)
  	if err != nil {
  		return nil, status.Errorf(codes.Internal, "failed to marshal JobConfig - %s", err)
  	}
  
  	launchCfg := def.Config
  	launchCfg.Mapper = def.mapperID()
  	launchCfg.Params = cfgBlob
  
  	jid, err := impl.ctl.LaunchJob(c, &launchCfg)
  	if err != nil {
  		return nil, toStatus(err)
  	}
  
  	return &api.JobID{JobId: int64(jid)}, nil
  }
docs: // LaunchJob implements the corresponding RPC method, see the proto doc.