require to add document about how to configure the logging

[jinluyang]

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Feature Request

If this is a feature request, please fill out the following form in full:

Describe the problem the feature is intended to solve

There is no document about how to configure the logging, about where to find the log ,and how often we sample the log. And an example would be better

Describe the solution

Add in your document

Describe alternatives you've considered

No

Additional context

I have searched all the document and the source code. It seems the ServerRequestLogger is always null?