Imports golang.org/x/sync/semaphore github.com/dustin/go-humanize github.com/gonejack/go-epub golang.org/x/sync/errgroup github.com/gabriel-vasile/mimetype github.com/gonejack/email github.com/schollz/progressbar/v3 github.com/PuerkitoBio/goquery Standard library imports bytes context encoding/base64 errors fmt io io/ioutil log net/http net/url os path/filepath strings time mime crypto/md5 html