+-- | A custom type for request message that doesn't
+-- need a response type, allows us to infer the request
+-- message type without using proxies.
+data RequestMessage' a = RequestMessage' T.Text LspId ClientMethod a
+
+instance ToJSON a => ToJSON (RequestMessage' a) where
+ toJSON (RequestMessage' rpc id method params) =
+ object ["jsonrpc" .= rpc, "id" .= id, "method" .= method, "params" .= params]
+
+