Log spamming 'Fallback handler could not load library'

[eamonwoortman]

When doing a request(sync or async) the Unity log will output the following message:

Fallback handler could not load library C:/path/to/unity_app/unity_app_Data/Mono/System/Library/Frameworks/Security.framework/Security
Fallback handler could not load library C:/path/to/unity_app/unity_app_Data/Mono/.\/System/Library/Frameworks/Security.framework/Security

It looks like it's trying to load a security framework which isn't supported in the .Net3.5 Unity subset.
Despite the log message, the request is working without any problems.