code: public void logMessageForTask(String taskId, String logMessage) {
          Preconditions.checkArgument(StringUtils.isNotBlank(taskId), "Task id cannot be blank");
          stub.addLog(
                  TaskServicePb.AddLogRequest.newBuilder()
                          .setTaskId(taskId)
                          .setLog(logMessage)
                          .build()
          );
      }
docs: Log execution messages for a task.
  
  @param taskId     id of the task
  @param logMessage the message to be logged