We seem to find that the problem is with the fact that events (unfortunately we have been naive to enable all events) are enabled on the server and the server is trying to send the events to the clients. And hence the presence of org.apache.ignite.internal.util.nio.GridNioServer$WriteRequestImpl

We are now trying go avoid usage of Ignite Events (we wanted to leverage the expiry event), disable all the events and have our own custom mechanism to determine the expiry.

We are still experimenting.