Fix multi block change cloning

Fixes #990

src/main/java/com/comphenix/protocol/reflect/cloning/BukkitCloner.java

@@ -82,6 +82,7 @@ public class BukkitCloner implements Cloner {
 		fromWrapper(MinecraftReflection::getNBTBaseClass, NbtFactory::fromNMS);
 		fromWrapper(MinecraftReflection::getIChatBaseComponentClass, WrappedChatComponent::fromHandle);
 		fromWrapper(WrappedVillagerData::getNmsClass, WrappedVillagerData::fromHandle);
+		fromConverter(MinecraftReflection::getSectionPositionClass, BukkitConverters.getSectionPositionConverter());
 
 		try {
 			fromManual(ComponentConverter::getBaseComponentArrayClass, source ->

src/main/java/com/comphenix/protocol/utility/MinecraftReflection.java

@@ -1872,6 +1872,10 @@ public class MinecraftReflection {
 		return getCraftBukkitClass("CraftSound");
 	}
 
+	public static Class<?> getSectionPositionClass() {
+		return getMinecraftClass("SectionPosition");
+	}
+
 	// ---- ItemStack conversions
 	private static Object itemStackAir = null;
 	private static Method asNMSCopy = null;

src/test/java/com/comphenix/protocol/events/PacketContainerTest.java

@@ -560,6 +560,9 @@ public class PacketContainerTest {
 
 		packet.getSectionPositions().writeSafely(0, new BlockPosition(42, 43, 44));
 		assertEquals(new BlockPosition(42, 43, 44), packet.getSectionPositions().readSafely(0));
+
+		PacketContainer clone = packet.deepClone();
+		assertNotSame(clone, packet);
 	}
 
 	/**