a mail sender can produce transmitter and send_email



 send with string
 
 ```

 let rt = tokio::runtime::Runtime::new().unwrap();

 rt.block_on(async {
     //from:senderAccoun
     //smtp_site:use which website to send email
     //password:senderPassword(it can be origin password)
     let mailer = MailerSender {
         from: "<sender@qq.com>".to_string(),
         password: "<senderPassword>".to_string(),
        smtp_site: "smtp.qq.com".to_string(),
     };
     //send_mail params
     //send_email(&self,reciever,email_topic,content(it can be string and html),attachment_name,attachment_path)
     //if dont send attachment,attachment_name and attachment_path fill None
     let _send_result = MailerSender::send_email(
         &mailer,
         "1984850802@qq.com".to_string(),
         "hell".to_string(),
         "hello,surprise".to_string(),
         None,
         None,
     )
     .await;
 });
 
 ```
 
 
 send with html
 
 ```

 let rt = tokio::runtime::Runtime::new().unwrap();
 rt.block_on(async {
     let mailer = MailerSender {
         from: "<sender@qq.com>".to_string(),
         password: "<senderPassword>".to_string(),
        smtp_site: "smtp.qq.com".to_string(),
     };
     let _send_result = MailerSender::send_email(
         &mailer,
         "1984850802@qq.com".to_string(),
         "hell".to_string(),
         "<h1 style='color:red'>hello,surprisess</h1>".to_string(),
         None,
         None,
     )
     .await;
 });
 
 ```
 
 
send content and  attachment
 
 ```

let rt = tokio::runtime::Runtime::new().unwrap();
rt.block_on(async {
    let mailer = MailerSender {
        from: "1984850802@qq.com".to_string(),
        password: "sfckoixahcpodcbb".to_string(),
        smtp_site: "smtp.qq.com".to_string(),
    };
    let _send_result = MailerSender::send_email(
        &mailer,
        "3502728398@qq.com".to_string(),
        "邮件".to_string(),
        "<h1 style='color:red'>hello,surprise</h1>".to_string(),
        Some("1.pdf".to_string()),
        Some("resume.pdf".to_string()),
    )
    .await;
});
```