[Feature Request] Support Signals in `insert`/`update`/`delete` in Postgres using `returning`
I'm unsure that this can be done cleanly and correctly, so I'm not inclined to implement or merge an implementation. Briefly, what are your concerns? Where would you install the signal hooks? What would they do? How would you make them work on SQLite and MySQL, which do not have `returning` clause support? They can be installed the same way they are now. They could function the same way, by mapping the signal handler over the iterable or providing a hook for passing the collection. 

They wouldn't work on SQLite or MySQL, just like `returning` doesn't work on them. Going to close this as I'm not interested in the feature, but feel free to implement it in a third-party module.
It would appear that Postgres can support signals using `returning`.

It should be able to easily support `post_*` signals using returning. The performance penalty should be worth the consistency in `update` vs. `save`.

Supporting `pre_*` signals would be a bit painful as you'd need to execute the save/insert using returning in an atomic block, reverting it before the block ends, fire the `pre_*` signal, replay the query, and then finally fire the `post_*` signal. The performance penalty here has the potential to be severe.

Thoughts? Would a PR be welcomed?