squash: implement feedback per review from @mcollina

Author: apapirovski

lib/_tls_wrap.js

@@ -295,6 +295,7 @@ function TLSSocket(socket, options) {
   this.alpnProtocol = null;
   this.authorized = false;
   this.authorizationError = null;
+  this[kRes] = null;
 
   // Wrap plain JS Stream into StreamWrap
   var wrap;
@@ -409,20 +410,25 @@ TLSSocket.prototype._wrapHandle = function(wrap) {
   res._secureContext = context;
   res.reading = handle.reading;
   this[kRes] = res;
-  Object.defineProperty(handle, 'reading', {
-    get: () => {
-      return this[kRes].reading;
-    },
-    set: (value) => {
-      this[kRes].reading = value;
-    }
-  });
+  defineHandleReading(this, handle);
 
   this.on('close', onSocketCloseDestroySSL);
 
   return res;
 };
 
+// This eliminates a cyclic reference to TLSWrap
+// Ref: https://github.com/nodejs/node/commit/f7620fb96d339f704932f9bb9a0dceb9952df2d4
+function defineHandleReading(socket, handle) {
+  Object.defineProperty(handle, 'reading', {
+    get: () => {
+      return socket[kRes].reading;
+    },
+    set: (value) => {
+      socket[kRes].reading = value;
+    }
+  });
+}
 
 function onSocketCloseDestroySSL() {
   // Make sure we are not doing it on OpenSSL's stack