Make vocab mapping optional

[meminkula]

This Pull Request addresses the issue of unnecessary vocabulary mapping tensors (t2d and d2t) being required for Eagle3Speculator models that utilize the full verifier vocabulary (as detailed in Issue #200). The core change involves updating the init method to accept t2d and d2t as optional arguments. The buffer registration logic in init and the mapping application in the forward pass are now conditional on these tensors being present. This ensures that users running full-vocab Eagle3 models can cleanly omit these buffers, which reduces checkpoint size and simplifies the developer workflow by removing the requirement for redundant "no-op" tensors. I'm excited to contribute this fix to the project.

Note: that was my first contribute. I hope i can be helpfull.

[shanjiaz]

Can we remove this import if it's not used?

[fynnsu]

Hi @meminkula, thank you for contributing. Since this is your first contribution, maybe I can give you some pointers to get you started:

• The focus of Create Eagle3DraftModels which use the full verifier vocab #200 is on the Eagle3DraftModel which is located here. We're actually in the process of deprecating and removing the Eagle3Speculator model you modified, so no changes are needed for that.
• When contributing to open source projects in general, it's important to keep the changes as minimal as possible. So changes like adding a django import or implementing the full forward function aren't necessary for this issue, and can distract from the focus of the pr.
• Lastly, we have some additional requirements when contributing to this repo that require you follow code formatting and linting steps before submitting. There's more information on that here

Let me know if you have any questions.