Non-nullable field '_subscriptionHandler' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_testObserver' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_client' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_server' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.' (https://aka.ms/dotnet-warnings/SYSLIB0014)

Possible null reference assignment.

Possible null reference assignment.

Possible null reference assignment.

Non-nullable field '_currentStream' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable property 'Key' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Key' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Key' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Data' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Key' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.