我正在嘗試在 Go (Golang) 中發(fā)送一封包含電子郵件正文和文件附件（CSV 文件）的電子郵件。我遵循mime多部分消息的標(biāo)準(zhǔn)，但是我不太熟悉遵循該標(biāo)準(zhǔn)的消息的結(jié)構(gòu)。我模糊地遵循一位同事的Python代碼片段作為使用Python庫email（我認(rèn)為這是來自標(biāo)準(zhǔn)庫）的指南，例如MIMEText和MIMEMultipart.執(zhí)行以下 Go 代碼時(shí)，電子郵件正文未顯示：這有什么問題嗎？如何發(fā)送包含該文件附件和電子郵件正文的電子郵件？該函數(shù)應(yīng)返回一個(gè)字節(jié)切片，用作smtp.SendMail從 Go 標(biāo)準(zhǔn)庫調(diào)用的參數(shù)。請參閱下面的注釋，了解收到的電子郵件發(fā)生的情況（ 和THIS DOES NOT SHOW UP [...]）THIS ALSO DOES NOT SHOW UP [...]。func msgWithAttachment(subject, filePath string) ([]byte, error) {    // this is the separator used for the various parts of the MIME message structure    // identified as "boundary"    bPlaceholder := "our-custom-separator"    // the message setup of the common/standard initial part    mime := bytes.NewBuffer(nil)    mime.WriteString(fmt.Sprintf("Subject: %s\r\nMIME-Version: 1.0\r\n", subject))    mime.WriteString(fmt.Sprintf("Content-Type: multipart/mixed; boundary=%s\r\n", bPlaceholder))    // THIS DOES NOT SHOW UP AS THE BODY OF THE EMAIL...    // mime.WriteString("\r\n")    // mime.WriteString(fmt.Sprintf("--%s\r\n", bPlaceholder))    // mime.WriteString("This should be the email message body (v1)...")    // mime.WriteString("\r\n")    // THIS ALSO DOES NOT SHOW UP AS THE BODY OF THE EMAIL...    // BUT IS NEEDED OTHERWISE THE EMAIL MESSAGE SEEMS TO CONTAIN AS ATTACHMENT THE EMAIL MESSAGE ITSELF    // (CONTAINING ITSELF THE REAL ATTACHMENT)    mime.WriteString(fmt.Sprintf("--%s\r\n", bPlaceholder))    mime.WriteString("Content-Type: text/plain; charset=utf-8\r\n")    mime.WriteString("This should be the email message body (v2)...")}