Attachment constructor
      
      Attachment({ 
    
    
- AttachmentDataRef? attachmentDataRef,
- String? contentName,
- String? contentType,
- String? downloadUri,
- DriveDataRef? driveDataRef,
- String? name,
- String? source,
- String? thumbnailUri,
Implementation
Attachment({
  this.attachmentDataRef,
  this.contentName,
  this.contentType,
  this.downloadUri,
  this.driveDataRef,
  this.name,
  this.source,
  this.thumbnailUri,
});