Transfer {dynamic_repo_module, dynamic_repo} across processes

[spacebat]

This allows for the info used in Ecto.Repo.put_dynamic_repo\1 to carry over to the process actually performing the query.

Contributor checklist

• Bug fixes include regression tests
• Chores
• Documentation changes
• Features include unit/acceptance tests
• Refactoring
• Update dependencies

[zachdaniel]

This should be doable with a custom tracer as discussed here: https://elixirforum.com/t/using-an-ash-resource-with-a-dynamic-repository/61138/4?u=zachdaniel

[zachdaniel]

Ah, I see the issue is that you don't have the query. Perhaps we can expand the tracer api to get the subject being used to start a new process.

[zachdaniel]

Actually your preparation to set the process context and a custom tracer together should do what you want.

[spacebat]

Zach was right, the tracer approach worked