Problem retrieving attached file name in imapclient

In go 1.21.6 mime/multipart/multipart.go line 88

// FileName returns the filename parameter of the Part's Content-Disposition
// header. If not empty, the filename is passed through filepath.Base (which is
// platform dependent) before being returned.
func (p *Part) FileName() string {
	if p.dispositionParams == nil {
		p.parseContentDisposition()
	}
	filename := p.dispositionParams["filename"]
	if filename == "" {
		return ""
	}
	// RFC 7578, Section 4.2 requires that if a filename is provided, the
	// directory path information must not be used.
	return filepath.Base(filename)
}

If the RFC2047 encoded filename includes β€œ/”, the file name may be truncated and returned in β€œreturn filepath.Base(filename)”.
Is there any other way to get the normal filename?