refactor(flash): move remoteAddr to options bag (#17913)

Applies suggestion from #17912

cli/tests/unit/flash_test.ts

@@ -89,14 +89,13 @@ Deno.test({ permissions: { net: true } }, async function httpServerBasic() {
   const listeningPromise = deferred();
 
   const server = Deno.serve({
-    handler: async (request, getRemoteAddr) => {
+    handler: async (request, { remoteAddr }) => {
       // FIXME(bartlomieju):
       // make sure that request can be inspected
       console.log(request);
       assertEquals(new URL(request.url).href, "http://127.0.0.1:4501/");
       assertEquals(await request.text(), "");
-      const addr = getRemoteAddr();
-      assertEquals(addr.hostname, "127.0.0.1");
+      assertEquals(remoteAddr.hostname, "127.0.0.1");
       promise.resolve();
       return new Response("Hello World", { headers: { "foo": "bar" } });
     },

cli/tsc/dts/lib.deno.unstable.d.ts

@@ -1163,6 +1163,18 @@ declare namespace Deno {
    */
   export function funlockSync(rid: number): void;
 
+  /** **UNSTABLE**: New API, yet to be vetted.
+   *
+   * Information for a HTTP request.
+   *
+   * @category HTTP Server
+  */
+   export interface ServeHandlerInfo {
+     /** The remote address of the connection. */
+    remoteAddr: Deno.NetAddr;
+  }
+
+
   /** **UNSTABLE**: New API, yet to be vetted.
    *
    * A handler for HTTP requests. Consumes a request and returns a response.
@@ -1173,7 +1185,7 @@ declare namespace Deno {
    *
    * @category HTTP Server
    */
-  export type ServeHandler = (request: Request, getRemoteAddr: () => Deno.NetAddr) => Response | Promise<Response>;
+  export type ServeHandler = (request: Request, info: ServeHandlerInfo) => Response | Promise<Response>;
 
   /** **UNSTABLE**: New API, yet to be vetted.
    *

ext/flash/01_http.js

@@ -579,16 +579,19 @@ function createServe(opFn) {
             );
 
             let resp;
+            let remoteAddr;
             try {
-              resp = handler(req, () => {
+              resp = handler(req, {
+                get remoteAddr() {
+                  if (!remoteAddr) {
                     const { 0: hostname, 1: port } = core.ops.op_flash_addr(
                       serverId,
                       i,
                     );
-                return {
-                  hostname,
-                  port,
-                };
+                    remoteAddr = { hostname, port };
+                  }
+                  return remoteAddr;
+                },
               });
               if (ObjectPrototypeIsPrototypeOf(PromisePrototype, resp)) {
                 PromisePrototypeCatch(