KVBlockScheme
Block-quantized KV storage selector: the block-wise online schemes whose scales ride inline in the cache's own block bytes (the append encodes each block as it writes). None_ keeps the cache at its float dtype.
Block-quantized KV storage selector: the block-wise online schemes whose scales ride inline in the cache's own block bytes (the append encodes each block as it writes). None_ keeps the cache at its float dtype.