added deep frozen state where chunk tickets will not be expiring as well, preventing chunks from unloading. Fixes #204

src/main/java/carpet/mixins/ChunkTicketManager_tickMixin.java

@@ -0,0 +1,23 @@
+package carpet.mixins;
+
+import carpet.helpers.TickSpeed;
+import net.minecraft.server.world.ChunkTicketManager;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+
+@Mixin(ChunkTicketManager.class)
+public class ChunkTicketManager_tickMixin
+{
+    @Shadow private long age;
+
+    @Inject(method = "purge", at = @At("HEAD"), cancellable = true)
+    private void pauseTicketSystem(CallbackInfo ci)
+    {
+        // pausing expiry of tickets
+        // that will prevent also chunks from unloading, so require a deep frozen state
+        if (!TickSpeed.process_entities && TickSpeed.deepFreeze) age--;
+    }
+}

src/main/java/carpet/mixins/MinecraftServer_tickspeedMixin.java

@@ -120,7 +120,7 @@ public abstract class MinecraftServer_tickspeedMixin extends ReentrantThreadExec
 
             this.profiler.startTick();
             this.profiler.push("tick");
-            this.tick(TickSpeed.time_warp_start_time != 0 ? ()->true : this::shouldKeepTicking);
+            this.tick(TickSpeed.time_warp_start_time != 0 ? ()->!hasRunningTasks() : this::shouldKeepTicking);
             this.profiler.swap("nextTickWait");
             this.field_19249 = true;
             this.field_19248 = Math.max(Util.getMeasuringTimeMs() + /*50L*/ msThisTick, this.timeReference);