docs: function makeHeaders(conf, payload) {
    var headers;
    function iterateHeaders(memo, key) {
      if (conf.context[constants.headers[key]]) {
        memo[constants.headerPrefix + constants.headers[key]] = conf.context[constants.headers[key]];
      }
      return memo;
    }
    if (conf.scope && conf.scope & constants.scopes.NONE) {
      headers = {};
    } else if (conf.scope && conf.scope & constants.scopes.APP_ONLY) {
      headers = ['APPCLAIMS'].reduce(iterateHeaders, {});
    } else {
      headers = Object.keys(constants.headers).reduce(iterateHeaders, {});
    }
  
    if (payload) {
      headers['Content-Length'] = payload.length.toString();
    }
  
    return extend({
      'Accept': 'application/json',
      'Connection': 'close',
      'Content-Type': 'application/json; charset=utf-8',
      'User-Agent': USER_AGENT
    }, headers, conf.headers || {});
  }