Lazily instantiate DrawBuffers

- Iris/Oculus create wrapper RenderTypes whose DrawBuffers are never
used. Creating the DrawBuffer on retrieval solves this inefficiency.
- Add 1.18.2 as a Minecraft version to the issue template

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -90,6 +90,7 @@ body:
             label: Minecraft Version
             description: The version of Minecraft you were using when the bug occured
             options:
+                - "1.18.2"
                 - "1.18.1"
                 - "1.18"
                 - "1.17.1"

src/main/java/com/jozufozu/flywheel/backend/instancing/DrawBuffer.java

@@ -2,6 +2,8 @@ package com.jozufozu.flywheel.backend.instancing;
 
 import java.nio.ByteBuffer;
 
+import org.jetbrains.annotations.ApiStatus;
+
 import com.jozufozu.flywheel.backend.model.BufferBuilderExtension;
 import com.jozufozu.flywheel.backend.model.DirectVertexConsumer;
 import com.mojang.blaze3d.platform.MemoryTracker;
@@ -20,6 +22,7 @@ public class DrawBuffer {
 	private ByteBuffer backingBuffer;
 	private int expectedVertices;
 
+	@ApiStatus.Internal
 	public DrawBuffer(RenderType parent) {
 		this.parent = parent;
 	}

src/main/java/com/jozufozu/flywheel/mixin/RenderTypeMixin.java

@@ -14,11 +14,14 @@ import net.minecraft.client.renderer.RenderType;
 public class RenderTypeMixin implements RenderTypeExtension {
 
 	@Unique
-	private final DrawBuffer flywheel$drawBuffer = new DrawBuffer((RenderType) (Object) this);
+	private DrawBuffer flywheel$drawBuffer;
 
 	@Override
 	@Nonnull
 	public DrawBuffer flywheel$getDrawBuffer() {
+		if (flywheel$drawBuffer == null) {
+			flywheel$drawBuffer = new DrawBuffer((RenderType) (Object) this);
+		}
 		return flywheel$drawBuffer;
 	}
 }