[Passing score blocker] `ParquetReader` involves a CPU time in `get_sample` 5x / 4x times longer than the I/O time

[wolfgang-desalvador]

Testing flux model on multiple CPU architectures and collecting traces with DFTRACER, the time for getting the next sample with ParquetReader is spent for approximately 80% on the deserialization part rather than in I/O.

For the case of UNET3D and NPZ reader, this was not higher than 20-30%

Also, there seems to be a considerable impact of the CPU architecture in the deserialization time.

This may impact the calculation of the Accelerator Utilization % as mainly influenced by elements not strictly related to storage performance.

This could potentially impact other models using ParquetReader

[wolfgang-desalvador]

First potential improvement -> mlcommons/DLIO_local_changes#13