Optional ReadonlycontentThe inline content identifier, without angle brackets.
Optional ReadonlycontentThe media type. Defaults to application/octet-stream.
ReadonlydataThe raw attachment content. The caller retains ownership.
Optional ReadonlyfilenameThe attachment filename. It may be empty.
Optional ReadonlyinlineMarks the attachment for inline display, for example a cid: image.
A message attachment.
The attachment data is retained by reference until the message is built. Callers must not mutate it in the meantime.