Expanded Hopper API

== AT ==
public net.minecraft.world.level.block.entity.HopperBlockEntity setCooldown(I)V
public net.minecraft.world.level.block.entity.HopperBlockEntity cooldownTime

paper-server/src/main/java/org/bukkit/craftbukkit/block/CraftHopper.java

@@ -40,4 +40,17 @@ public class CraftHopper extends CraftLootable<HopperBlockEntity> implements Hop
     public CraftHopper copy(Location location) {
         return new CraftHopper(this, location);
     }
+
+    // Paper start - Expanded Hopper API
+    @Override
+    public void setTransferCooldown(final int cooldown) {
+        com.google.common.base.Preconditions.checkArgument(cooldown >= 0, "Hooper transfer cooldown cannot be negative (" + cooldown + ")");
+        getSnapshot().setCooldown(cooldown);
+    }
+
+    @Override
+    public int getTransferCooldown() {
+        return getSnapshot().cooldownTime;
+    }
+    // Paper end - Expanded Hopper API
 }