IBM Cloud Object Storage - what is the data consistency / visibility model?

What warranty does IBM Cloud Object Storage provide regarding data consistency / visibility? AWS is mostly read-write-write for new objects, and eventual consistency for updates / deletes. So what is the data consistency model for IBM COS? And I doubt that object locking is supported, but I would like to make sure that this is really not possible (it would be great if it was!).

For reference, AWS states its data consistency model here :

Amazon S3 provides post-write consistency for PUTS of new objects in your S3 bucket across all regions with one caveat. The caveat is that if you make a HEAD or GET request to a key name (to determine if the object exists) before creating the object, Amazon S3 provides eventual read-after-write consistency.

Amazon S3 offers possible consistency for rewriting PUTS and DELETES across all regions.

Single key updates are atomic. For example, if you click on an existing key, a subsequent read can return old data or updated data, but will never write corrupted or partial data.

and regarding object locking:

Amazon S3 does not currently support object locking. If there are two PUT requests to the same key at the same time, the request with the last timestamp wins. If this is a problem, you will need to create an object locking mechanism in your application.

Updates are key based; there is no way to do atomic updates by keys. For example, you cannot make the update of one key dependent on the update of another key unless you create this functionality in your application.