getSupportedProtocols method Null safety
getSupportedProtocols RPC is used to determine which protocols are
supported by the current server.
The result of this call should be intercepted by any middleware that extends the core VM service protocol and should add its own protocol to the list of protocols before forwarding the response to the client.
@override Future<ProtocolList> getSupportedProtocols() => _call('getSupportedProtocols');