Create or replace a key-value data entry for the client.

Create or replace a key-value data entry for the client.

Each entry is associated with a datastore, an optional project, an optional user, and a key. Creating a request that duplicates this quadruple will replace rather than create the value in the key-value pair.

Entries associated with neither a project nor user are considered global; those associated with a project but no user are project- default; those associated with a user but no project are user-default; and those associated with both a project and a user are user-project specific. When listing key-value data, all four of these values, if existing, will be returned.