Fix a deadlock that could happen in offline mode when shutting down the server

CraftBukkit-Patches/0056-BungeeCord-Support.patch

@@ -74,6 +74,33 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
      }
      // Spigot end
  
+@@ -0,0 +0,0 @@ public class LoginListener implements PacketLoginInListener, IUpdatePlayerListBo
+             this.networkManager.handle(new PacketLoginOutEncryptionBegin(this.j, this.server.P().getPublic(), this.e));
+         } else {
+             // Spigot start
+-            try {
+-                initUUID();
+-                new LoginHandler().fireEvents();
+-            } catch (Exception ex) {
+-                disconnect("Failed to verify username!");
+-                server.server.getLogger().log(java.util.logging.Level.WARNING, "Exception verifying " + i.getName(), ex);
+-            }
++            initUUID();
++            new Thread(new Runnable() {
++
++                @Override
++                public void run() {
++                    try{
++                        new LoginHandler().fireEvents();
++                    } catch (Exception ex) {
++                        disconnect("Failed to verify username!");
++                        server.server.getLogger().log(java.util.logging.Level.WARNING, "Exception verifying " + i.getName(), ex);
++                    }
++                }
++            }).start();
+             // Spigot end
+         }
+ 
 diff --git a/src/main/java/net/minecraft/server/NetworkManager.java b/src/main/java/net/minecraft/server/NetworkManager.java
 index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
 --- a/src/main/java/net/minecraft/server/NetworkManager.java