Socket send function hangs

Question

Hi, 
 I have a custom board with nrf9160 and I'm using it to send messages to the AWS server via mqtt. I managed to reproduce a bug where the TLS socket send function hangs (similar to - https://devzone.nordicsemi.com/f/nordic-q-a/62249/hang-in-sendmsg-on-the-nrf9160 ). I was using v1.3 of ncs. 
 Steps to reproduce - 
 
 Connect to LTE netwrok. 
 Connect to AWS via MQTT 
 When a successful connection is established, send a disconnect message 
 When successfully disconnected, reconnect and keep repeating this loop 
 On the 21st connection/disconnection cycle the function gets stuck in the mqtt_client_tls_write function while calling the 
 
 send(client->transport.tls.sock, data + offset, datalen - offset, 0); 
 
function

I switched to the latest master branch of ncs and changed the send function to send(client->transport.tls.sock, data + offset, datalen - offset, MSG_DONTWAIT) Now the send function doesn't hang but returns a value of -1 and the errno is -EAGAIN when I follow the steps to reproduce this bug. 
 How do I handle the socket timeout gracefully? After this timeout, if I try to reconnect to AWS I get 
 aws_iot: getaddrinfo, error -10 aws_iot: client_broker_init, error: -10 
 and I have to restart the device to get it working again I also noticed an error case which doesn't seem to be handled in aws_iot.c. When the socket send function returns -1, then in file mqtt.c, the function client_connect calls client_disconnect which in turn calls disconnect_event_notify function. This notifies the aws_iot client with 
 
 evt . type = MQTT_EVT_CONNACK ; 
 evt . result = - ECONNREFUSED ; 
 
 which is not handled properly in aws_iot.c. Handling this properly still causes the same error I mentioned before though. 
 
 Any help will be appreciated. Thanks in advance! 
 
 Nikil