Add Loop::getHandle

Previously we advised to use Loop::get()->getHandle(), because it's a method only required by very few components, namely the filesystem libraries, which need the underlying handle to operate.

We argued that we get a smaller autocomplete list that way. I think consistency is more important.

src/Loop.php

@@ -422,6 +422,19 @@ public static function getInfo()
         return $driver->getInfo();
     }
 
+    /**
+     * Get the underlying loop handle.
+     *
+     * Example: the `uv_loop` resource for `libuv` or the `EvLoop` object for `libev` or `null` for a native driver.
+     *
+     * @return null|object|resource The loop handle the event loop operates on. `null` if there is none.
+     */
+    public static function getHandle()
+    {
+        $driver = self::$driver ?: self::get();
+        return $driver->getHandle();
+    }
+
     /**
      * Disable construction as this is a static class.
      */

src/Loop/Driver.php

@@ -277,9 +277,6 @@ abstract public function getInfo();
      *
      * Example: the `uv_loop` resource for `libuv` or the `EvLoop` object for `libev` or `null` for a native driver.
      *
-     * Note: This function is *not* exposed in the `Loop` class. Users shall access it directly on the respective loop
-     * instance.
-     *
      * @return null|object|resource The loop handle the event loop operates on. `null` if there is none.
      */
     abstract public function getHandle();