func (p *postmark) AttachmentInlineFile(file string) Mailer {
	p.attachmentInlineFiles = append(p.attachmentInlineFiles, file)
	return p
}
AttachmentInlineFile set email inline attachment
package gomailer
import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strings"
)
const (
	postmarkBaseURL = "https://api.postmarkapp.com"
	postmarkMaxFileSize int64 = 5 * 1000000
	postmarkMaxReceipents = 50
)
type (
	postmark struct {
		c                     client
		configs               Configs
		from                  address
		toList                []address
		ccList                []address
		bccList               []address
		replyTo               address
		subject               string
		bodyHTML              string
		bodyText              string
		attachmentFiles       []string
		attachmentInlineFiles []string
		attachments           []attachment
	}
	postmarkAttachment struct {
		Name        string `json:"Name"`
		Content     string `json:"Content"`
		ContentType string `json:"ContentType"`
		ContentID   string `json:"ContentID"`
	}
)
func (p *postmark) messageURL() string {
	url := postmarkBaseURL
	if p.configs.BaseURL != "" {
		url = p.configs.BaseURL
	}
	return fmt.Sprintf("%s/email", url)
}
func (p *postmark) From(name, from string) Mailer {
	p.from = address{Name: name, Email: from}
	return p
}
func (p *postmark) To(name, to string) Mailer {
	p.toList = append(p.toList, address{Name: name, Email: to})
	return p
}
func (p *postmark) Cc(name, to string) Mailer {
	p.ccList = append(p.ccList, address{Name: name, Email: to})
	return p
}
func (p *postmark) Bcc(name, to string) Mailer {
	p.bccList = append(p.bccList, address{Name: name, Email: to})
	return p
}
func (p *postmark) ReplyTo(name, email string) Mailer {
	p.replyTo = address{Name: name, Email: email}
	return p
}
func (p *postmark) Subject(subject string) Mailer {
	p.subject = subject
	return p
}
func (p *postmark) BodyHTML(body string) Mailer {
	p.bodyHTML = body
	return p
}
func (p *postmark) BodyText(body string) Mailer {
	p.bodyText = body
	return p
}
func (p *postmark) AttachmentFile(file string) Mailer {
	p.attachmentFiles = append(p.attachmentFiles, file)
	return p
}