Error <T, TResult>' exists in both DLL ?

Hello,
I have a problem with my project I use WebSocket dll, and it seems to have a conflict with .net dll (in 2.0 or 4.0).
I don't know how to edit dll.
The UI package seems to be related to the error.

ERROR: "C:\Program Files\Unity\Hub\Editor\2019.3.0b6\Editor\Data\Resources\PackageManager\BuiltInPackages\com.unity.ugui\Runtime\UI\Core\Layout\LayoutUtility.cs(148,74): error CS0433: The type 'Func<T, TResult>' exists in both 'WebSocket4Net, Version=0.14.1.0, Culture=neutral, PublicKeyToken=eb4e154b696bf72a' and 'mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'r

May Someone help me ?

 

I have that same error with a different package:

Code (CSharp):

1. C:\Program Files\Unity\Hub\Editor\2019.2.9f1\Editor\Data\Resources\PackageManager\BuiltInPackages\com.unity.ugui\Runtime\UI\Core\Layout\LayoutUtility.cs(134,74): error CS0433: The type 'Func<T, TResult>' exists in both 'WebSocket4Net, Version=0.14.1.0, Culture=neutral, PublicKeyToken=eb4e154b696bf72a' and 'netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51'

 

Yes, the dlls such as socketIO, WebSocket... use the same "<T, TResult>" as the package manager.
The solution is on the hand of unity, as I understand it.
Unless somebody can save me ?

 

Are there any other ways to use socketio in Unity 2019 and above?

 

Hello from 2021