Add server switch event

api/src/main/java/net/md_5/bungee/api/event/ServerSwitchEvent.java

@@ -0,0 +1,21 @@
+package net.md_5.bungee.api.event;
+
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.ToString;
+import net.md_5.bungee.api.connection.ProxiedPlayer;
+import net.md_5.bungee.api.plugin.Event;
+/**
+ * Called when a player has changed servers.
+ */
+@Data
+@ToString(callSuper = false)
+@EqualsAndHashCode(callSuper = false)
+public class ServerSwitchEvent extends Event
+{
+
+    /**
+     * Player whom the server is for.
+     */
+    private final ProxiedPlayer player;
+}