tweek flush and replace exception with error log

src/main/java/me/cortex/voxy/client/core/VoxyRenderSystem.java

@@ -253,6 +253,8 @@ public class VoxyRenderSystem {
         try {this.renderer.shutdown();this.chunkBoundRenderer.free();} catch (Exception e) {Logger.error("Error shutting down renderer", e);}
         Logger.info("Shutting down post processor");
         if (this.postProcessing!=null){try {this.postProcessing.shutdown();} catch (Exception e) {Logger.error("Error shutting down post processor", e);}}
+        Logger.info("Flushing download stream");
+        DownloadStream.INSTANCE.flushWaitClear();
 
         //Release hold on the world
         this.worldIn.releaseRef();

src/main/java/me/cortex/voxy/client/core/rendering/hierachical/HierarchicalOcclusionTraverser.java

@@ -12,6 +12,7 @@ import me.cortex.voxy.client.core.rendering.building.RenderGenerationService;
 import me.cortex.voxy.client.core.rendering.util.DownloadStream;
 import me.cortex.voxy.client.core.rendering.util.PrintfDebugUtil;
 import me.cortex.voxy.client.core.rendering.util.UploadStream;
+import me.cortex.voxy.common.Logger;
 import me.cortex.voxy.common.util.MemoryBuffer;
 import me.cortex.voxy.common.world.WorldEngine;
 import org.lwjgl.system.MemoryUtil;
@@ -320,7 +321,8 @@ public class HierarchicalOcclusionTraverser {
     private void forwardDownloadResult(long ptr, long size) {
         int count = MemoryUtil.memGetInt(ptr);ptr += 8;//its 8 since we need to skip the second value (which is empty)
         if (count < 0 || count > 50000) {
-            throw new IllegalStateException("Count unexpected extreme value: " + count);
+            Logger.error(new IllegalStateException("Count unexpected extreme value: " + count));
+            return;
         }
         if (count > (this.requestBuffer.size()>>3)-1) {
             //This should not break the synchonization between gpu and cpu as in the traversal shader is

src/main/java/me/cortex/voxy/client/core/rendering/util/DownloadStream.java

@@ -149,6 +149,21 @@ public class DownloadStream {
     }
 
     //Synchonize force flushes everything
+    public void waitDiscard() {
+        glFinish();
+        var fence = new GlFence();
+        glFinish();
+        while (!fence.signaled())
+            Thread.onSpinWait();
+        fence.free();
+        while (!this.frames.isEmpty()) {
+            var frame = this.frames.pop();
+            while (!frame.fence.signaled()) Thread.onSpinWait();
+            frame.allocations.forEach(this.allocationArena::free);
+            frame.fence.free();
+        }
+    }
+
     public void flushWaitClear() {
         glFinish();
         this.tick();