How to convert MS Word (*.docx) file into PDF using UniOffice?

/*
 * This example showcases PDF generation from docx document with UniOffice package.
 */

package main

import (
    "fmt"
    "log"
    "os"

    unipdflicense "github.com/unidoc/unipdf/v4/common/license"

    "github.com/unidoc/unioffice/v2/common/license"
    "github.com/unidoc/unioffice/v2/document"
    "github.com/unidoc/unioffice/v2/document/convert"
)

func init() {
    // Make sure to load your metered License API key prior to using the library.
    // If you need a key, you can sign up and create a free one at https://cloud.unidoc.io
    err := unipdflicense.SetMeteredKey(os.Getenv(`UNIDOC_LICENSE_API_KEY`))
    if err != nil {
        fmt.Printf("ERROR: Failed to set metered key: %v\n", err)
        fmt.Printf("Make sure to get a valid key from https://cloud.unidoc.io\n")
        fmt.Printf("If you don't have one - Grab one in the Free Tier at https://cloud.unidoc.io\n")
        panic(err)
    }

    // This example requires both for unioffice and unipdf.
    err = license.SetMeteredKey(os.Getenv(`UNIDOC_LICENSE_API_KEY`))
    if err != nil {
        fmt.Printf("ERROR: Failed to set metered key: %v\n", err)
        fmt.Printf("Make sure to get a valid key from https://cloud.unidoc.io\n")
        fmt.Printf("If you don't have one - Grab one in the Free Tier at https://cloud.unidoc.io\n")
        panic(err)
    }
}

var filenames = []string{
    "chart",
    "headers_footers",
    "image_square",
    "table",
    "text_only_portrait",
    "text_only_landscape",
    "textbox_anchor",
    "textbox_inline",
}

func main() {
    for _, filename := range filenames {
        outputPath := filename + ".pdf"
        doc, err := document.Open(filename + ".docx")
        if err != nil {
            log.Fatalf("error opening document: %s", err)
        }
        defer doc.Close()
        c := convert.ConvertToPdf(doc)

        err = c.WriteToFile(outputPath)
        if err != nil {
            log.Fatalf("error converting document: %s", err)
        }
    }
}