Build JSON in executor

[amelchio]

Description:

This is to help with situations like this.

Related issue (if applicable): fixes #

Checklist:

• The code change is tested and works locally.

If the code does not interact with devices:

• Local tests with tox run successfully.
• Tests have been added to verify that the new code works.

[balloob]

I wonder if we should add a keyword only parameter to self.json to offload JSONifying to the executor.

[amelchio]

I was hoping that it would not be needed much.

I can make the change if you want but I am not sure how to offload since self.json appears to have no hass handle handy?

[balloob]

Ah yes, you're right. And it is also a callback and not a coroutine. Let's just limit it to history and logbook for now then.

[pvizeli]

Yeah good catch. If we see more problems, we can make a more generic fix, but for now it should be okay.