Add cache usage property to ChatSampler and Sampler

[arJ-V]

Cache Usage Monitoring Enhancement

Overview

Previously, a TODO was marked to add a property showing how much of the cache is used. This is useful for debugging and monitoring cache usage during multi-turn conversations.

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Previous State

• No easy way to check cache usage without accessing internal last_state directly
• Users had to manually compute state.used_cache_length / cache_length

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Changes

Added Cache Usage Monitoring

Cache usage monitoring was added to both sampler classes:

• ChatSampler.cache_usage property

  • Returns a (used, total) tuple
  • Returns None if no sampling has been performed yet

• Sampler.get_cache_usage() static method — For stateless usage with the low-level API

  • Takes a SamplingState and cache_length as parameters

[pannaga-33]

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