net: fix bufferSize

bufferSize should only look at writableLength otherwise it will
always show more than what is actually pending.

PR-URL: #34088
Refs: #34078
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Anna Henningsen <[email protected]>

Author: ronag

lib/net.js

@@ -552,7 +552,7 @@ ObjectDefineProperty(Socket.prototype, 'readyState', {
 ObjectDefineProperty(Socket.prototype, 'bufferSize', {
   get: function() {
     if (this._handle) {
-      return this[kLastWriteQueueSize] + this.writableLength;
+      return this.writableLength;
     }
   }
 });

test/parallel/test-tls-buffersize.js

@@ -31,7 +31,7 @@ server.listen(0, common.mustCall(() => {
 
     for (let i = 1; i < iter; i++) {
       client.write('a');
-      assert.strictEqual(client.bufferSize, i + 1);
+      assert.strictEqual(client.bufferSize, i);
     }
 
     client.on('finish', common.mustCall(() => {

test/parallel/test-tls-streamwrap-buffersize.js

@@ -56,7 +56,7 @@ const net = require('net');
 
         for (let i = 1; i < iter; i++) {
           client.write('a');
-          assert.strictEqual(client.bufferSize, i + 1);
+          assert.strictEqual(client.bufferSize, i);
         }
 
         // It seems that tlsSockets created from sockets of `Duplex` emit no