OptionalcontentAn optional filename for the file (e.g., "document.pdf").
The media_type (MIME type) of the part content (e.g., "text/plain", "application/json", "image/png").
This field is available for all part types.
Optional. metadata associated with this part.
Partrepresents a container for a section of communication content. Parts can be purely textual, some sort of file (image, video, etc) or a structured data blob (i.e. JSON).