[WIP] Spec infer with EAGLE2

[yukavio]

Motivation

Accelerate the model inference by speculative inference (EAGLE2).

Modifications

It will be provided soon.

Checklist

• Format your code according to the Contributor Guide.
• Add unit tests as outlined in the Contributor Guide.
• Update documentation as needed, including docstrings or example tutorials.

[Qiubo1]

hello, whether this code supports the multiple request sepc?