The Mail service can send email messages to one or more recipients. A message contains a subject, a plaintext body, and an optional HTML body. It can also contain file attachments and a limited set of headers.

  • 邮件服务可以发送邮件到一个或多个收件人
  • Message 包含一个 主题， 一个plaintext 块，一个可选的 html块
  • Message 也可以包含附件
  • Message 也可以包含 header 集合（有限的）

When an application calls the Mail service to send a message, the message is queued, and the call returns immediately. The Mail service uses standard procedures for contacting each recipient’s mail server, delivering the message, and retrying if the mail server cannot be contacted.

  • 当app调用 mail service 时， message 被放到 队列中，然后调用return，调用结束。