Merge pull request #2447 from Kaiepi/async-introspection

Document async socket .native-descriptor

Author: JJ

doc/Type/IO/Socket/Async.pod6

@@ -291,4 +291,10 @@ Returns the port of the local end of this socket.
 
 Returns the port of the remote end of this socket.
 
+=head2 method native-descriptor
+
+    method native-descriptor(--> Int)
+
+Returns the file descriptor of this socket.
+
 =end pod