Add PlayerConnectionCloseEvent

This event is invoked when a player has disconnected. It is guaranteed that,
if the server is in online-mode, that the provided uuid and username have been
validated.

The event is invoked for players who have not yet logged into the world, whereas
PlayerQuitEvent is only invoked on players who have logged into the world.

The event is invoked for players who have already logged into the world,
although whether or not the player exists in the world at the time of
firing is undefined. (That is, whether the plugin can retrieve a Player object
using the event parameters is undefined). However, it is guaranteed that this
event is invoked AFTER PlayerQuitEvent, if the player has already logged into
the world.

This event is guaranteed to never fire unless AsyncPlayerPreLoginEvent has
been called beforehand, and this event may not be called in parallel with
AsyncPlayerPreLoginEvent for the same connection.

Cancelling the AsyncPlayerPreLoginEvent guarantees the corresponding
PlayerConnectionCloseEvent is never called.

The event may be invoked asynchronously or synchronously. As it stands,
it is never invoked asynchronously. However, plugins should check
Event#isAsynchronous to be future-proof.

On purpose, the deprecated PlayerPreLoginEvent event is left out of the
API spec for this event. Plugins should not be using that event, and
how PlayerPreLoginEvent interacts with PlayerConnectionCloseEvent
is undefined.

paper-api/src/main/java/com/destroystokyo/paper/event/player/PlayerConnectionCloseEvent.java

@@ -0,0 +1,83 @@
+package com.destroystokyo.paper.event.player;
+
+import java.net.InetAddress;
+import java.util.UUID;
+import org.bukkit.event.Event;
+import org.bukkit.event.HandlerList;
+import org.bukkit.event.player.AsyncPlayerPreLoginEvent;
+import org.bukkit.event.player.PlayerQuitEvent;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * <p>
+ * This event is invoked when a player has disconnected. It is guaranteed that,
+ * if the server is in online-mode, that the provided uuid and username have been
+ * validated.
+ * <p>
+ * The event is invoked for players who have not yet logged into the world, whereas
+ * {@link PlayerQuitEvent} is only invoked on players who have logged into the world.
+ * <p>
+ * The event is invoked for players who have already logged into the world,
+ * although whether or not the player exists in the world at the time of
+ * firing is undefined. (That is, whether the plugin can retrieve a Player object
+ * using the event parameters is undefined). However, it is guaranteed that this
+ * event is invoked AFTER {@link PlayerQuitEvent}, if the player has already logged into the world.
+ * <p>
+ * This event is guaranteed to never fire unless {@link AsyncPlayerPreLoginEvent} has
+ * been fired beforehand, and this event may not be called in parallel with
+ * {@link AsyncPlayerPreLoginEvent} for the same connection.
+ * <p>
+ * Cancelling the {@link AsyncPlayerPreLoginEvent} guarantees the corresponding
+ * {@code PlayerConnectionCloseEvent} is never called.
+ * <p>
+ * The event may be invoked asynchronously or synchronously. Plugins should check
+ * {@link Event#isAsynchronous()} and handle accordingly.
+ */
+@NullMarked
+public class PlayerConnectionCloseEvent extends Event {
+
+    private static final HandlerList HANDLER_LIST = new HandlerList();
+
+    private final UUID playerUniqueId;
+    private final String playerName;
+    private final InetAddress ipAddress;
+
+    @ApiStatus.Internal
+    public PlayerConnectionCloseEvent(final UUID playerUniqueId, final String playerName, final InetAddress ipAddress, final boolean async) {
+        super(async);
+        this.playerUniqueId = playerUniqueId;
+        this.playerName = playerName;
+        this.ipAddress = ipAddress;
+    }
+
+    /**
+     * Returns the {@code UUID} of the player disconnecting.
+     */
+    public UUID getPlayerUniqueId() {
+        return this.playerUniqueId;
+    }
+
+    /**
+     * Returns the name of the player disconnecting.
+     */
+    public String getPlayerName() {
+        return this.playerName;
+    }
+
+    /**
+     * Returns the player's IP address.
+     */
+    public InetAddress getIpAddress() {
+        return this.ipAddress;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return HANDLER_LIST;
+    }
+
+    public static HandlerList getHandlerList() {
+        return HANDLER_LIST;
+    }
+}