The variable 'e' is declared but never used

Use "Async" suffix in names of methods that return an awaitable type (https://github.com/Microsoft/vs-threading/blob/main/doc/analyzers/VSTHRD200.md)

This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.

Observe the awaitable result of this method call by awaiting it, assigning to a variable, or passing it to another method (https://github.com/Microsoft/vs-threading/blob/main/doc/analyzers/VSTHRD110.md)

'JsonRPCPlugin.JsonRPC' hides inherited member 'JsonRPCPluginBase.JsonRPC'. Use the new keyword if hiding was intended.

The annotation for nullable reference types should only be used in code within a '#nullable' annotations context.

'WebClient.WebClient()' is obsolete: 'WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete.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

Possible null reference assignment.

The variable 'e' is declared but never used

Synchronously waiting on tasks or awaiters may cause deadlocks. Use await or JoinableTaskFactory.Run instead. (https://github.com/Microsoft/vs-threading/blob/main/doc/analyzers/VSTHRD002.md)