Implement an event handler

src/main/java/emu/grasscutter/server/event/ServerEvent.java

@@ -0,0 +1,17 @@
+package emu.grasscutter.server.event;
+
+/**
+ * An event that is related to the internals of the server.
+ */
+public abstract class ServerEvent extends Event {
+    protected final Type type;
+    
+    public ServerEvent(Type type) {
+        this.type = type;
+    }
+    
+    public enum Type {
+        DISPATCH,
+        GAME
+    }
+}