The shutdown request is sent from the client to the server. It asks the server to shut down, but to not exit (otherwise the response might not be delivered correctly to the client).
There is a separate exit notification that asks the server to exit. Clients must not send any notifications other than exit or requests to a server to which they have sent a shutdown request. Clients should also wait with sending the exit notification until they have received a response from the shutdown request.
The server will error with Lsp.ProtocolError.INVALID_REQUEST if it receives any requests after a shutdown request.