Function biased_entropy_rate_bytes 

pub fn biased_entropy_rate_bytes(data: &[u8], max_order: i64) -> f64

Compute biased entropy rate Ĥ_biased(X) bits per symbol.

This uses the full plugin estimator (training on the whole text, then scoring the same text). While biased as a source entropy estimate, it is mathematically consistent for similarity metrics like Mutual Information and NED.