proposal: add Reset field to sync.Pool to reset item before putting it back to the pool

[mantzas]

When putting an item back to the pool the fields are left with the any values it has at this point.
The next caller to the Get will get this dirty object.

My proposal is to create a Reset function field, much like the New one, which takes as an argument the object in question. This reset function should be called right before the item is put back to the internal store.

[mvdan]

Why not simply wrap Put in a function that does this?

[josharian]

The Reset function will have to accept an interface{}, which means that you'll have to type assert inside it, at which point I suspect most people will choose to simply reset inline, or have a typed helper func that calls Put, as @mvdan suggested.

[bradfitz]

sync.Pool is a low-level interface. It's a feature that you can get a "dirty" (read: initialized) item out of the pool again. If you need to zero some things, you can do so before Put or after Get.

[mantzas]

@bradfitz makes sense