Not sure what the reason for it is but I sometimes get the error { [Error: socket hang up] code: 'ECONNRESET' } but I cannot simply reproduce it.
I have a trace of when it happens, in this case I'm running NODE_DEBUG=net so it logs a lot, see here:
https://gist.github.com/editedredx/94e3ed4fdfadf8cf6418

Running windows and the request at the top is a https POST Firefox makes automatically every X minutes. This often seems to be the culprit however it looks like some other requests can also trigger it.