Separate TickingChunkLoader from ChunkLoader

this makes it possible to keep chunks loaded without ticking them.

src/world/ChunkLoader.php

@@ -24,7 +24,7 @@ declare(strict_types=1);
 namespace pocketmine\world;
 
 /**
- * If you want to keep chunks loaded, implement this interface and register it into World. This will also tick chunks.
+ * If you want to keep chunks loaded, implement this interface and register it into World.
  *
  * @see World::registerChunkLoader()
  * @see World::unregisterChunkLoader()
@@ -34,13 +34,4 @@ namespace pocketmine\world;
  */
 interface ChunkLoader{
 
-	/**
-	 * @return float
-	 */
-	public function getX();
-
-	/**
-	 * @return float
-	 */
-	public function getZ();
 }

src/world/TickingChunkLoader.php

@@ -0,0 +1,42 @@
+<?php
+
+/*
+ *
+ *  ____            _        _   __  __ _                  __  __ ____
+ * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
+ * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
+ * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
+ * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * @author PocketMine Team
+ * @link http://www.pocketmine.net/
+ *
+ *
+*/
+
+declare(strict_types=1);
+
+namespace pocketmine\world;
+
+/**
+ * TickingChunkLoader includes all of the same functionality as ChunkLoader (it can be used in the same way).
+ * However, using this version will also cause chunks around the loader's reported coordinates to get random block
+ * updates.
+ */
+interface TickingChunkLoader extends ChunkLoader{
+
+	/**
+	 * @return float
+	 */
+	public function getX();
+
+	/**
+	 * @return float
+	 */
+	public function getZ();
+}

src/world/World.php

@@ -951,6 +951,10 @@ class World implements ChunkManager{
 		$randRange = (int) ($randRange > $this->chunkTickRadius ? $this->chunkTickRadius : $randRange);
 
 		foreach($this->loaders as $loader){
+			if(!($loader instanceof TickingChunkLoader)){
+				//TODO: maybe we should just not track non-ticking chunk loaders here?
+				continue;
+			}
 			$chunkX = (int) floor($loader->getX()) >> 4;
 			$chunkZ = (int) floor($loader->getZ()) >> 4;