Serious mistake MixedRealityToolkit

[HBJKZLH]

When I wrote socket and IO and Thread related code in the program, untiy packaging times was wrong,
The socket.Connect function is not supported.
The socket.Receive function is not supported, and the socket.Send function is not supported.
The filestream.close function is not supported,
New Thread(recv) is not supported,
Does not support Thread. IsBackground,
Does not support Thread. To Start,
What else can I develop?
Do you want me to develop model viewers only?

[HBJKZLH]

'FileStream' does not contain a definition for 'Close' and no extension method 'Close' accepting a first argument of type 'FileStream' could be found (are you missing a using directive or an assembly reference?)

'Socket' does not contain a definition for 'Connect' and no extension method 'Connect' accepting a first argument of type 'Socket' could be found (are you missing a using directive or an assembly reference?)

'Thread' does not contain a constructor that takes 1 arguments

'Thread' does not contain a definition for 'IsBackground' and no extension method 'IsBackground' accepting a first argument of type 'Thread' could be found (are you missing a using directive or an assembly reference?)

'Thread' does not contain a definition for 'Start' and no extension method 'Start' accepting a first argument of type 'Thread' could be found (are you missing a using directive or an assembly reference?)

'Socket' does not contain a definition for 'Receive' and no extension method 'Receive' accepting a first argument of type 'Socket' could be found (are you missing a using directive or an assembly reference?)

'Socket' does not contain a definition for 'Send' and no extension method 'Send' accepting a first argument of type 'Socket' could be found (are you missing a using directive or an assembly reference?)