the JMap data source id
the attachment to download
JMap.Attachment
.download("f47ac10b-58cc-4372-a567-0e02b2c3d479", "d9428888-122b-11e1-b85c-61cd3cbb3210")
.then(({ data, headers }) => console.log("Downloaded attachment", headers["content-type"], data.size))
.catch(error => console.error("Download failed", error))
JMap.Attachment.download
Downloads an attachment and returns the raw binary data plus the HTTP headers sent by the server.