CenterNet with Keypoints - TFRecord format requirements

Prerequisites

Please answer the following question for yourself before submitting an issue.

• [x ] I checked to make sure that this issue has not been filed already.

1. The entire URL of the documentation with the issue

https://github.com/tensorflow/models/blob/master/research/object_detection/g3doc/using_your_own_dataset.md

2. Describe the issue

There is no sample script or description of how to encode the Keypoint information for CenterNet. I'd like to see a sample script and specific clarifications on whether the Keypoint coordinates need to be normalized by image width and height like with the bounding boxes.