"PlatformNotSupportedException: Operation is not supported on this platform." error thrown when using HttpClient PatchAsync

How to reproduce:
1. Open the attached project "HttpClient PatchAsync Regression (IN-8860).zip"
2. Open Assets/Scenes/SampleScene.unity
3. Enter Play Mode

Expected results: No errors in the Console window
Actual results: "PlatformNotSupportedException: Operation is not supported on this platform." error thrown in the Console window

Reproducible with: 2021.3.6f1, 2022.1.9f1, 2022.2.0a19, 2023.1.0a3
Could not test with: 2020.3.37f1 (compilation errors in the Console window)

Reproducible on: Windows 10