documentations for driver class

[jeongukjae]

URL(s) with the issue:

• https://github.com/tensorflow/tfx/blob/master/tfx/dsl/components/base/base_driver.py
• https://www.tensorflow.org/tfx/guide/custom_component

Description of issue (what needs changing):

Clear description:

When customizing TFX components, sometimes Driver class is very important. But couldn't find docs for the Driver class for detailed use-case. So it may helpful for advanced users.

[briron]

Yeah, I think we missed the documentation of the Driver class. Thanks for pointing this out.

Before documentation, I want to clarify if you need a general explanation of the Driver class or there is a specific example that you want to know from this. Any clarification will help us to make better docs.

[jeongukjae]

@briron thanks. I could understand by following course and tfx GitHub.

• https://www.cloudskillsboost.google/course_templates/191

The concept was clear, but it should be great if the docs clarify compatibilities (supported runners). I dig into the Driver for my custom component, and found that it is not supported in pipelines that running in Vertex AI (#6722).