ImageFileAttachment constructor
Creates an ImageFileAttachment with the given name, MIME type, and bytes.
name is the name of the image attachment. mimeType is the MIME type of
the image. bytes is the binary content of the image.
Implementation
ImageFileAttachment({
required super.name,
required super.mimeType,
required super.bytes,
}) : assert(Attachment._isImage(mimeType));