Migrate Carpet Mixin names to mojang mappings

src/main/java/carpet/mixins/DistanceManager_spawnChunksMixin.java

@@ -0,0 +1,55 @@
+package carpet.mixins;
+
+import carpet.fakes.ChunkTicketManagerInterface;
+import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
+import net.minecraft.server.level.DistanceManager;
+import net.minecraft.server.level.Ticket;
+import net.minecraft.server.level.TicketType;
+import net.minecraft.util.SortedArraySet;
+import net.minecraft.util.Unit;
+import net.minecraft.world.level.ChunkPos;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+
+import java.util.Iterator;
+
+@Mixin(DistanceManager.class)
+public abstract class DistanceManager_spawnChunksMixin implements ChunkTicketManagerInterface
+{
+    @Shadow @Final private Long2ObjectOpenHashMap<SortedArraySet<Ticket<?>>> tickets;
+
+    @Shadow protected abstract void removeTicket(long pos, Ticket<?> ticket);
+
+    @Shadow public abstract <T> void addRegionTicket(TicketType<T> type, ChunkPos pos, int radius, T argument);
+
+    @Override
+    public void changeSpawnChunks(ChunkPos chunkPos,  int distance)
+    {
+        long pos = chunkPos.toLong();
+        SortedArraySet<Ticket<?>> set = tickets.get(pos);
+        Ticket existingTicket = null;
+        if (set != null)
+        {
+            Iterator<Ticket<?>> iter = set.iterator();
+            while(iter.hasNext())
+            {
+                Ticket ticket = iter.next();
+                if (ticket.getType() == TicketType.START)
+                {
+                    existingTicket = ticket;
+                    iter.remove();
+                }
+            }
+            set.add(existingTicket);
+        }
+        // the reason we are removing the ticket this way is that there are sideeffects of removal
+        if (existingTicket != null)
+        {
+            removeTicket(pos, existingTicket);
+        }
+        // set optionally new spawn ticket
+        if (distance > 0)
+            addRegionTicket(TicketType.START, chunkPos, distance, Unit.INSTANCE);
+    }
+}