Add Player#getHiddenEntities API

patches/server/0016-Add-Player-getHiddenEntities-API.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Lexi <lexi@qixils.dev>
+Date: Thu, 23 Jun 2022 22:03:18 -0400
+Subject: [PATCH] Add Player#getHiddenEntities API
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+index abcce6bd0b32d0188751393a6f56f2e82530912c..c4533c3a479046f81273d7bdb13d6f4fea24037d 100644
+--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
++++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+@@ -1680,6 +1680,17 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
+             registerEntity(player);
+         }
+     }
++
++    // Parchment start
++    @Override
++    public Set<UUID> getHiddenEntities(Plugin plugin) {
++        return hiddenEntities.entrySet().stream()
++            .filter(entry -> entry.getValue().contains(CraftPlayer.getPluginWeakReference(plugin)))
++            .map(Map.Entry::getKey)
++            .collect(java.util.stream.Collectors.toSet());
++    }
++    // Parchment end
++
+     public void setPlayerProfile(com.destroystokyo.paper.profile.PlayerProfile profile) {
+         ServerPlayer self = getHandle();
+         self.gameProfile = com.destroystokyo.paper.profile.CraftPlayerProfile.asAuthlibCopy(profile);