The content length in bytes of the file that will be uploaded
The base64 encoded MD5 checksum of the file contents that will be uploaded
The MIME type of the file that will be uploaded
Optional Write Lock
Enforces conflict checking when updating an existing data item. This field should be omitted when creating a new data item. When updating an existing item, omitting this field ignores write conflicts. When present, an error response will be returned if the writeLock in the request does not match the stored writeLock.