Multi Beam Text Streamer
Author: MosheOfer1
Pull request: yes

# What does this PR do?

Add MultiBeamTextStreamer for real-time beam search monitoring

Adds MultiBeamTextStreamer class that enables real-time tracking and viewing of multiple beam outputs during generation. Features:

- Track and manage multiple beam candidates simultaneously
- Support beam switching and history tracking
- Provide callbacks for beam updates and completion events
- Handle beam search state management and cleanup

Try it out: https://huggingface.co/spaces/mosheofer1/multi_beam_text_streamer

This streamer is useful for interactive applications, debugging beam search, and creating UIs that display beam search progress in real-time.

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Issue number: #35451


## Before submitting
- [x] This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
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- [x] Did you write any new necessary tests?


## Who can review?

Anyone in the community is free to review the PR once the tests have passed. Feel free to tag
members/contributors who may be interested in your PR.
@gante 
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Models:

- text models: @ArthurZucker
- vision models: @amyeroberts, @qubvel
- speech models: @ylacombe, @eustlb
- graph models: @clefourrier

Library:

- flax: @sanchit-gandhi
- generate: @zucchini-nlp (visual-language models) or @gante (all others)
- pipelines: @Rocketknight1
- tensorflow: @gante and @Rocketknight1
- tokenizers: @ArthurZucker
- trainer: @muellerzr and @SunMarc
- chat templates: @Rocketknight1

Integrations:

- deepspeed: HF Trainer/Accelerate: @muellerzr
- ray/raytune: @richardliaw, @amogkam
- Big Model Inference: @SunMarc
- quantization (bitsandbytes, autogpt): @SunMarc @MekkCyber

Documentation: @stevhliu

HF projects:

- accelerate: [different repo](https://github.com/huggingface/accelerate)
- datasets: [different repo](https://github.com/huggingface/datasets)
- diffusers: [different repo](https://github.com/huggingface/diffusers)
- rust tokenizers: [different repo](https://github.com/huggingface/tokenizers)

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- Flax: @sanchit-gandhi
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Comments:
Hi @MosheOfer1 👋 

Apologies for my delay and for the bold request that follows 🤗 
We're vectorizing beam search in [this PR](https://github.com/huggingface/transformers/pull/35802) -- would you be up for modifying this PR so as to work there?

This is a much appreciated feature, and I will build upon this PR if you're not available to continue it!