// Verify it is a regular file, otherwise subsequent Seek is
	// undefined.
	if !st.Mode().IsRegular() {
		return 0, errIsNotRegular
	}

	if verifier == nil {
		n, err = file.ReadAt(buffer, offset)
		return int64(n), err
	}

	h := verifier.algorithm.New()
	if _, err = io.Copy(h, io.LimitReader(file, offset)); err != nil {
		return 0, err
	}

        this.protocols = protocolsCopy.unmodifiable()
      }

    /**
     * Sets the verifier used to confirm that response certificates apply to requested hostnames for
     * HTTPS connections.
     *
     * If unset, a default hostname verifier will be used.
     */
    fun hostnameVerifier(hostnameVerifier: HostnameVerifier) =
      apply {