An error message displays when the client is actively disconnected for any of these reasons:
  • The client has too many backed up messages (ErrSlowConsume).
  • The client is sending too many messages (ErrSlowRead).
  • The message size is too large (Message too big)
  • There are intermittent network issues.
Most failure cases trigger an error message—specifically, a message with the type "error". This can be helpful when implementing a client or debugging issues. 
{
  "type": "error",
  "message": "error message"
  /* ... */
}