Reset of observe request fails after write to response

[Merisho]

Hello. I see following behavior on CoAP server: after any notification write to response stream on observe request Error: Empty messages must be empty exception appears.

const coap    = require('coap')
    , server  = coap.createServer()

server.on('request', function(req, res) {
  if (req.headers['Observe'] !== 0)
    return res.end(new Date().toISOString() + '\n')

  var interval = setInterval(function() {
    res.write(new Date().toISOString() + '\n')
    res.reset();      //  <-------------- here it fails
  }, 1000)

  res.on('finish', function(err) {
    clearInterval(interval)
  })
})

server.listen(function() {
  console.log('server started')
})

I follow up with stack trace and can say that this happens because of not empty res._packet.options after first res.write (so if I do reset before first write there is no error).

Related: #154

@mcollina @GiedriusM Could you please advice?

P.S. When I do res._packet.options = [] manually before reset it seems to be ok (no exception), but how can I track that connection has been dropped? No 'end' events on client side for ObserveReadStream instance is triggered.

[stale]

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[stale]

This issue has been automatically closed because of inactivity. Please open a new issue if still relevant and make sure to include all relevant details, logs and reproduction steps. Thank you for your contributions.