How to report a crashed language server to the user

Question

My VS Code extension is starting a language server (win, exe) on basis of the language server protocol via a socket connection. Under some circumstances (coding problems) that languageserver.exe crashes, so no support for the VS Code editor is available any more. The end-user does not get informed about the loss of support, except that the editor screen does not get any refreshes by a language server validation.

What would be the best concept to detect and report an unavailable language server service to the end-user?

Should there be a cyclic "ping" to the language server or is there a special request with a timeout? Or is there a feature in VS Code which tests the connection to the language server?