[Documentation] Estimating (or Checking) Allocated Memory

### Describe the documentation issue

I'm wondering how one would check or estimate how much off-heap memory is allocated by the ONNX runtime. For context I'm running an ONNX model inside Java process and need to know how much off-heap memory is allocated for the ONNX model and inputs.

### Page / URL

_No response_

Start by reviewing the ONNX Runtime Java usage and the issue's question about off-heap memory for the model and inputs. Determine which existing documentation or entry point explains memory allocation, and define done as documenting a supported way to estimate or check that allocation.

Written by the indexing model from the issue text.