When you are trying to use the transfer command it does not check if the player is already in that server.

How to reproduce the issue:

• Make two dedicated servers.
• Open the server.properties file, and change the server-port to 25566.
• Start the servers.
• Connect to it, and type this command: /transfer localhost 25566
• Once you are connected to the server, type the same command.
• Notice that you can connect multiple times to the same ip, same port.

Expected Behaviour:
There should be a message in chat that says "You are already connected to this server." which would prevent the player to join twice to the same server.

Actual Behaviour:
The player can connect to the same exact server multiple times even if they are there.