Function reshape_and_cache 

pub fn reshape_and_cache(
    gpu: &dyn GpuBackend,
    kernel: KernelHandle,
    key: DevicePtr,
    value: DevicePtr,
    k_cache: DevicePtr,
    v_cache: DevicePtr,
    slot_mapping: DevicePtr,
    num_tokens: u32,
    num_kv_heads: u32,
    head_dim: u32,
    block_size: u32,
    key_stride: u32,
    value_stride: u32,
    _cache_stride: u64,
    stream: u64,
) -> Result<()>

2026-09-25: Copy BF16 K and V rows into the paged BF16 cache at slot_mapping (kernel reshape_and_cache_flash), one block per token. key_stride / value_stride are the row strides in elements. _cache_stride is not passed to the kernel, which derives the block stride from block_size.