code: function _websocketPort(ctx, port) {
    const forwarded = ctx.header['x-forwarded-proto'];
    const protocol = forwarded ? forwarded.split(',')[0] : undefined;
    return protocol === 'https' ? 443 : port;
  }
docs: @private
  
  Hack to help determine Glitch WebSocket port
  
  @param {Object} ctx
  @param {number} port - server port number
  @return {number} WebSocket port number