Function quantized_sum_i4 

pub fn quantized_sum_i4(
    packed: &[u8],
    count: usize,
    params: &QuantParamsI4,
) -> f64

Sum dequantized i4 (packed) values using BinnedAccumulator.

packed contains pairs of i4 values packed into bytes. count is the total number of i4 elements (may be odd).