QAT for object detection models?

System information

• TensorFlow version (you are using):2.6
• Are you willing to contribute it (Yes/No):

Motivation

Need to run OD models on device, after QAT.

Describe the feature

Currently QAT only supports sequential and functional model, as stated in https://blog.tensorflow.org/2020/04/quantization-aware-training-with-tensorflow-model-optimization-toolkit.html
I looked into OD models and they are subclassed from tf.keras.layer. Even the backbone (e.g. feature extractor) is not a functional model (model._is_graph_network is False).

I used quantize_model() and it throws out error since it's not a keras model.

Describe how the feature helps achieve the use case

Describe how existing APIs don't satisfy your use case (optional if obvious)

As examples:

1. You tried using APIs X and Y and were able to do Z. However, that was not sufficient because of ...

2. You achieved your use case with the code snippet W. However, this was more difficult than it should be because of ... (e.g. ran into issue X or had
   to do Y).