Diesel 2.0 -- What goes here?

This category is the place to discuss what changes should land in Diesel 2.0, the timing of that version, and how we communicate it. See the second pinned thread for the discussion around timing and messaging. To propose a breaking change being made, you should create a new thread in this category with the following format:

Description of the change

What will get put in the changelog if we make this change?

Why is this needed?

A breaking change is not something to be taken lightly. What does this change enable? Why is it worth the cost to our users?

Why can’t this have a deprecation cycle?

The only breaking changes that will be permitted in Diesel 2.0 are those that could not have a deprecation cycle done for whatever reason. Every change proposed needs to justify why it can’t be done normally.

Expected user impact

Describe what code will be affected by this change. Consider user applications, custom connection adapters, and other plugin crates. If possible, point to some open source Diesel applications and describe if they’re affected and how much code has to change.

Migration strategy

For code that is affected, what changes will be required on their part? Is it possible for someone to write code that supports both 1.0 and 2.0? The changes required to user code should be minimal – No change will be accepted as a breaking change that is significantly more effort for our users than a normal deprecation would be.