_tls.js

// To cause warnings to be emitted, this needs to be run with:
//
//   NODE_EXTRA_CA_CERTS=x.pem
//
// and x.pem having invalid pem, perhaps a beginning of a cert without an end
// line, see below. My goal was to cause something to be printed between the
// BEGIN and END, no success.
//
// -----BEGIN CERTIFICATE-----
function log(s) {
  return function() {
    process._rawDebug(s);
  }
}
process.nextTick(log('A'));
new Promise(function(resolve) {
  log('p enter')();
  resolve();
}).then(log('p resolved'));

log('BEGIN')();
require('tls').createServer({})
log('END')();
process.nextTick(log('C'));