Inline message content.

Designed for use in %SparkPost.Transmission{content: ...}.

Fields

• from: ‘From’ address (email string | %SparkPost.Address)
• reply_to: the destination for replies to this message aka Reply-To (email string)
• headers: email headers (map)
• subject: email subject line
• text: plain text message body
• html: HTML-formatted message body
• attachments: file attachments (list of %SparkPost.Content.Attachment)
• inline_images: inline images (list of %SparkPost.Content.Attachment)

Note: at least one of text or html must be filled out.