[Stateful DataLoader] add utilities to inspect/modify dataloader state

[andrewkho]

🚀 The feature

State Dict utilities to inspect state

Motivation, pitch

We should provide some utilites for users to inspect and potentially modify the dataloader state. Currently the format of the dictionary is opaque, and we may want to make changes in the future. Instead of users inspecting and hard-coding paths, we should instead provide utilities to make it easy, and future-proof.

Current list of desired utilities:

• Retrieve state for worker 'i'
• Retrieve and update the number of steps to skip upon resume

Alternatives

No response

Additional context

No response