Add Debug loader using symfony/var-dumper, and Sleep Transformer to wait between stages

Author: camillebaronnet

src/Loader/Debug.php

@@ -0,0 +1,20 @@
+<?php
+
+namespace Camillebaronnet\ETL\Loader;
+
+use Generator;
+
+class Debug implements LoaderInterface, StreamLoaderInterface
+{
+    public function __invoke(array $data)
+    {
+        return dump($data);
+    }
+
+    public function stream(Generator $collection): void
+    {
+        foreach ($collection as $row) {
+            dump($row);
+        }
+    }
+}

src/Transformer/Sleep.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Camillebaronnet\ETL\Transformer;
+
+class Sleep implements TransformInterface
+{
+    public $seconds = 1;
+
+    /**
+     * The saved context, hydrated by the __invoke.
+     *
+     * @var array
+     */
+    protected $context = [];
+
+    /**
+     * The class entry point.
+     */
+    public function __invoke(array $data): array
+    {
+        sleep($this->seconds);
+
+        return $data;
+    }
+}