Initial client connection pipeline, this isn't done yet.

src/main/java/io/minimum/minecraft/velocity/proxy/ConnectedPlayer.java

@@ -1,6 +1,9 @@
 package io.minimum.minecraft.velocity.proxy;
 
-import io.minimum.minecraft.velocity.proxy.server.ServerConnection;
+import io.minimum.minecraft.velocity.protocol.packets.Disconnect;
+import net.kyori.text.TextComponent;
+import net.kyori.text.format.TextColor;
+import net.kyori.text.serializer.ComponentSerializers;
 
 import java.util.UUID;
 
@@ -31,4 +34,17 @@ public class ConnectedPlayer {
     public ServerConnection getConnectedServer() {
         return connectedServer;
     }
+
+    public void handleConnectionException(Throwable throwable) {
+        String error = "Exception: " + throwable.getClass().getName() + ": " + throwable.getMessage();
+
+        if (connectedServer == null) {
+            // The player isn't yet connected to a server - we should disconnect them.
+            Disconnect disconnect = new Disconnect();
+            disconnect.setReason(ComponentSerializers.JSON.serialize(TextComponent.of(error, TextColor.RED)));
+            connection.closeWith(disconnect);
+        } else {
+            // TODO
+        }
+    }
 }