why the yolov8 int8 quant using pytorch_quant is slower than trt --fp16 quant

[luoshiyong]

devicec : nvidia NX 1.using trt --fp16 /usr/src/tensorrt/bin/trtexec --onnx=best.onnx --workspace=4096 --saveEngine=best.engine --fp16 the result of infer speed is 36.8ms 2. using pytorch_quant int8 /usr/src/tensorrt/bin/trtexec --onnx=best.onnx --saveEngine=v8s_ptq.engine --int8 --workspace=4096 the result of infer speed is : 39.5ms

### Tasks