node/lib/internal/http.js

'use strict';

const timers = require('timers');

var dateCache;
function utcDate() {
  if (!dateCache) {
    const d = new Date();
    dateCache = d.toUTCString();
    timers.enroll(utcDate, 1000 - d.getMilliseconds());
    timers._unrefActive(utcDate);
  }
  return dateCache;
}
utcDate._onTimeout = function() {
  dateCache = undefined;
};

function ondrain() {
  if (this._httpMessage) this._httpMessage.emit('drain');
}

module.exports = {
  outHeadersKey: Symbol('outHeadersKey'),
  ondrain,
  utcDate
};