code: function parseResponseHeaders (headers) {
    var parsed = {};
  
    if (headers) {
      headers.split('\n').forEach(function (line) {
        var separatorIndex = line.indexOf(':');
        var key = line.substr(0, separatorIndex).trim().toLowerCase();
        var value = line.substr(separatorIndex + 1).trim().toLowerCase();
  
        if (key) {
          parsed[key] = value;
        }
      });
    }
  
    return parsed;
  }
docs: Parses HTTP response headers, and returns them as an object with header names as keys
  and header values as values.
  
  @param {?string} headers - Response headers, separated by CRLF
  @returns {object}