Does onnxruntime-openvino EP only use the operator acceleration of openvino?

@HectorSVC is already working on this.

Since Feb 18, 2023.

### Describe the issue

I want to ask about the underlying principle of onnxruntime EP.

### To reproduce

Because I found that the multithreading mechanism of onnxruntime seems to be different from that of openvino.

If onnxruntime-openvino is used, will ort use vino's asynchronous multithreading library? Or is it just using vino's optimization for graph optimization and operator optimization, and ort's is still useing his own Multi-thread mechanism?

There is another problem here. onnxruntime will optimize the Computational Graph, and openvino will also optimize the Computational Graph. If you use openvino EP, how do you know whose graph optimization is the best?

Thank you very much.

### Urgency

_No response_

### Platform

Linux

### OS Version

20.04

### ONNX Runtime Installation

Released Package

### ONNX Runtime Version or Commit ID

lastest

### ONNX Runtime API

Python

### Architecture

X64

### Execution Provider

Default CPU

### Execution Provider Library Version

_No response_