For secure connections where the Client is served over SSL, the message size is slightly greater and the below assert fails.
I replaced the != condition with < so that it fails only when message could not be send in full.
int MqttClient::endMessage()
{
if (!_txStreamPayload) {
if (!publishHeader(_txPayloadBufferIndex) ||
(clientWrite(_txPayloadBuffer, _txPayloadBufferIndex) != _txPayloadBufferIndex)) {
stop();
return 0;
}
}