Slow model loading

Hey,
I have been using coremltools for some time and model loading has been very fast, usually within seconds. I am using an ~150Mbs size mlpackage model with coremltool version 5.2.0. Recently, I upgraded to 6.2 and after this, the coreml model loading increased to 150secs.
Could anyone who faced a similar issue at any time during development help me in this regard.
my code is:

```
import coremltools as ct

model = ct.models.MLModel(model_path)

```

Thanks in advance!

system is mac m1 air, 8Gb mem

Start by reproducing the reported 150-second load with ct.models.MLModel(model_path) using the ~150 MB mlpackage on the stated Mac M1 environment, comparing coremltools 5.2.0 and 6.2. Inspect the model-loading path for the version-related regression. Done means the slowdown is reproducible, its cause is identified, and the affected behavior has a regression test or documented resolution.

Written by the indexing model from the issue text.