Kryonet threading

Hi guys,
I’m developing an mmorpg and I’m using kryonet. My question is: Are these instruction

connection.sendTCP(message);

or

server.sendToAllTCP(message);

going to slow my logic thread if inserted in my main logic thread? If, for example, a lot of data has to be sent, is this operation going to run on the logic thread (slowing it) or on a different thread?

Sorry for my English guys ç_ç