use internal symbol to read fd

ext/net/01_net.js

@@ -5,6 +5,7 @@ const {
   BadResourcePrototype,
   InterruptedPrototype,
   internalRidSymbol,
+  internalFdSymbol,
   createCancelHandle,
 } = core;
 import {
@@ -99,28 +100,26 @@ class Conn {
 
   #readable;
   #writable;
-  #fd = -1;
-
   constructor(rid, remoteAddr, localAddr, fd) {
     ObjectDefineProperty(this, internalRidSymbol, {
       __proto__: null,
       enumerable: false,
       value: rid,
     });
+    ObjectDefineProperty(this, internalFdSymbol, {
+      _proto_: null,
+      enumerable: false,
+      value: fd,
+    });
     this.#rid = rid;
     this.#remoteAddr = remoteAddr;
     this.#localAddr = localAddr;
-    this.#fd = fd;
   }
 
   get remoteAddr() {
     return this.#remoteAddr;
   }
 
-  get fd() {
-    return this.#fd;
-  }
-
   get localAddr() {
     return this.#localAddr;
   }

ext/net/lib.deno_net.d.ts

@@ -138,8 +138,6 @@ declare namespace Deno {
 
     readonly readable: ReadableStream<Uint8Array>;
     readonly writable: WritableStream<Uint8Array>;
-
-    readonly fd: number;
   }
 
   /** @category Network */

ext/node/polyfills/internal_binding/tcp_wrap.ts

@@ -27,6 +27,8 @@
 // TODO(petamoriken): enable prefer-primordials for node polyfills
 // deno-lint-ignore-file prefer-primordials
 
+import { core } from "ext:core/mod.js";
+const { internalFdSymbol } = core;
 import { notImplemented } from "ext:deno_node/_utils.ts";
 import { unreachable } from "ext:deno_node/_util/asserts.ts";
 import { ConnectionWrap } from "ext:deno_node/internal_binding/connection_wrap.ts";
@@ -131,8 +133,8 @@ export class TCP extends ConnectionWrap {
 
     super(provider, conn);
 
-    if (conn?.fd) {
-      this[fdSymbol] = conn.fd;
+    if (this[kStreamBaseField]) {
+      this[fdSymbol] = this[kStreamBaseField][internalFdSymbol];
     }
 
     // TODO(cmorten): the handling of new connections and construction feels