text: export class InvalidUrlError extends Error {
    /**
     * @param {string} message
     */
    constructor(message = 'invalid URL') {
      const status = 400
      super(createErrorHtmlContent(status, message))
      this.name = 'InvalidUrlError'
      this.status = status
      this.code = InvalidUrlError.CODE
      this.contentType = 'text/html'
    }
  }
  InvalidUrlError.CODE = 'ERROR_INVALID_URL'
  
  export class TimeoutError extends Error {
    /**
     * @param {string} message
     */
    constructor(message = 'Gateway Time-out') {
      const status = 408
      super(createErrorHtmlContent(status, message))
      this.name = 'TimeoutError'
      this.status = status
      this.code = TimeoutError.CODE
      this.contentType = 'text/html'
    }
  }
  TimeoutError.CODE = 'ERROR_TIMEOUT'
  
  export const createErrorHtmlContent = (status, message) => `<html>
  <head><title>${status} ${message}</title></head>
  <body>
  <div style="text-align:center">
  <h1>${status} ${message}</h1>
  </div>
  </body>
  </html>
  `
  