[Bug]: `RateLimiter` can not modify backoff behaviour of `perform_completion_with_backoff`

[lance6716]

crawl4ai version

current master

Expected Behavior

https://github.com/unclecode/crawl4ai/blob/02f3127deda707b948e1970699fceae214677b86/crawl4ai/utils.py#L1645C5-L1645C17

it can not be changed by outside function

Current Behavior

it can not be changed by outside function

Is this reproducible?

Yes

Inputs Causing the Bug

Steps to Reproduce

Code snippets

OS

not related

Python version

not related

Browser

No response

Browser version

No response

Error logs & Screenshots (if applicable)

No response