ValueError: train_pb2.load_all_detection_checkpoint_vars unsupported in TF2

Prerequisites

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

• [Y ] I checked to make sure that this feature has not been requested already.

1. The entire URL of the file you are using

https://github.com/tensorflow/models/tree/master/research/object_detection/...

2. Describe the feature you request

model_lib_v2.py doesn't support load_all_detection_checkpoint_vars now.
I wonder is it because some fundamental issues related to TF2 API or it's just you haven't got to it yet?
If it's the later, are you planning to support it in the future?

3. Additional context

4. Are you willing to contribute it? (Yes or No)

Yes, if provided with necessary help.