[@types/restify] Fix Callback Typing on Restify Metrics Plugin (#29785)

* fix typing on restify metrics plugin

* should be a function with typed arguments

* adding some comments to get another build to move the PR along

types/restify/index.d.ts

@@ -1417,22 +1417,32 @@ export namespace plugins {
      */
     function throttle(options?: ThrottleOptions): RequestHandler;
 
-    interface MetricsCallback {
+    type MetricsCallback = (
         /**
          *  An error if the request had an error
          */
-        err: Error;
+        err: Error,
 
-        metrics: MetricsCallbackOptions;
+        /**
+         *  Object that contains the various metrics that are returned
+         */
+        metrics: MetricsCallbackOptions,
 
-        req: Request;
-        res: Response;
+        /**
+         * The request obj
+         */
+        req: Request,
+
+        /**
+         * The response obj
+         */
+        res: Response,
 
         /**
          * The route obj that serviced the request
          */
-        route: Route;
-    }
+        route: Route,
+    ) => void;
 
     type TMetricsCallback = 'close' | 'aborted' | undefined;
 
@@ -1495,13 +1505,13 @@ export namespace plugins {
      * Listens to the server's after event and emits information about that request (5.x compatible only).
      *
      * ```
-     * server.on('after', plugins.metrics( (err, metrics) =>
+     * server.on('after', plugins.metrics({ server }, (err, metrics, req, res, route) =>
      * {
      *    // metrics is an object containing information about the request
      * }));
      * ```
      */
-    function metrics(opts: { server: Server }, callback: (options: MetricsCallback) => any): (...args: any[]) => void;
+    function metrics(opts: { server: Server }, callback: MetricsCallback): (...args: any[]) => void;
 
     /**
      * Parse the client's request for an OAUTH2 access tokensTable

types/restify/v5/index.d.ts

@@ -1251,13 +1251,13 @@ export namespace plugins {
      * Listens to the server's after event and emits information about that request (5.x compatible only).
      *
      * ```
-     * server.on('after', plugins.metrics( (err, metrics) =>
+     * server.on('after', plugins.metrics({ server }, (err, metrics, req, res, route) =>
      * {
      *    // metrics is an object containing information about the request
      * }));
      * ```
      */
-    function metrics(opts: { server: Server }, callback: (options: MetricsCallback) => any): (...args: any[]) => void;
+    function metrics(opts: { server: Server }, callback: MetricsCallback): (...args: any[]) => void;
 
     /**
      * Parse the client's request for an OAUTH2 access tokensTable