We should investigate implementing a general concept of a key format that is independent of the storage engine.

With the clustered indexes project, a new key format is used in WiredTiger's table creation, key_format=12s. Existing tables use key_format=q.

An approach for generalizing the key format could be to use a raw byte array, key_format=u. See https://source.wiredtiger.com/develop/group__wt.html#struct_w_t___i_t_e_m