Limit server to only send the packets it creates and only accept the packets the client creates

src/main/java/net/minecraft/server/PacketCounter.java

@@ -0,0 +1,18 @@
+package net.minecraft.server;
+
+class PacketCounter {
+
+    private int a;
+    private long b;
+
+    private PacketCounter() {}
+
+    public void a(int i) {
+        ++this.a;
+        this.b += (long) i;
+    }
+
+    PacketCounter(EmptyClass1 emptyclass1) {
+        this();
+    }
+}