How to add a copy button to a code block?

[yzxh24]

Is there an existing issue for this?

• I have searched the existing issues

The question

Hi all, I would like to ask if I add a copy button to the top right corner of the code block so that I can quickly copy the code inside, similar to the picture below:

[EchoEllet]

The code block is not customizable, but it's possible to replace it with another widget, possibly a code highlighter / viewer that already has a copy button.

[EchoEllet]

Yes, the screenshot in my question was generated from CustomBlockEmbed in the documentation.
However, there are two issues I can't deal with when using CustomBlockEmbed:

Please refer to #2146, and consider using the experimental property customLeadingBlockBuilder instead of CustomBlockEmbed to override the built-in code block instead of implementing a new custom embed.

allows to pass an Iterable? parameter, but it doesn't seem to be working correctly at the moment, I'm still trying to find out why

Could you provide a minimal example code? The toPlainText() extracts plain text without attributes or rich output. What are you using it for?