Values.UploadMetadataSourceFields to be used while uploading the attachment.
type nonrec t = {url : UploadMetadataUrl.t option;This is the pre-signed URL that can be used for uploading the file to Amazon S3 when used in response to StartAttachmentUpload.
*)urlExpiry : ISO8601Datetime.t option;The expiration time of the URL in ISO timestamp. It's specified in ISO 8601 format: yyyy-MM-ddThh:mm:ss.SSSZ. For example, 2019-11-08T02:41:28.172Z.
*)headersToInclude : UploadMetadataSignedHeaders.t option;The headers to be provided while uploading the file to the URL.
*)}val to_value :
t ->
[> `Structure of
(string
* [> `Map of
([> `String of UploadMetadataSignedHeadersKey.t ]
* [> `String of UploadMetadataSignedHeadersValue.t ])
list
| `String of UploadMetadataUrl.t ])
list ]