doc: add documentation for http.IncomingMessage$complete

Fixes: #8102

PR-URL: #23914
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

Author: jasnell

doc/api/http.md

@@ -1500,6 +1500,34 @@ added: v10.1.0
 The `message.aborted` property will be `true` if the request has
 been aborted.
 
+### message.complete
+<!-- YAML
+added: v0.3.0
+-->
+
+* {boolean}
+
+The `message.complete` property will be `true` if a complete HTTP message has
+been received and successfully parsed.
+
+This property is particularly useful as a means of determining if a client or
+server fully transmitted a message before a connection was terminated:
+
+```js
+const req = http.request({
+  host: '127.0.0.1',
+  port: 8080,
+  method: 'POST'
+}, (res) => {
+  res.resume();
+  res.on('end', () => {
+    if (!res.complete)
+      console.error(
+        'The connection was terminated while the message was still being sent');
+  });
+});
+```
+
 ### message.destroy([error])
 <!-- YAML
 added: v0.3.0