Create a FeedbackMessage object.
String content of the feedback. Maximum of 10000 characters.
Create time.
The image storing this feedback if the feedback is an image representing operator's comments.
Name of the feedback message in a feedback thread. Format: 'project/{project_id}/datasets/{dataset_id}/annotatedDatasets/{annotated_dataset_id}/feedbackThreads/{feedback_thread_id}/feedbackMessage/{feedback_message_id}'