Deprecate application/octet-stream encoding parameter in REST API

The REST API allows a client to encode application/octet-stream keys and values either in BASE64 or in an ad-hoc hex format, depending on the value of the encoding parameter.

REST, being based on HTTP, offers a more natural encoding of application/octet-stream:

• In the URI, the keys should be percent-encoded
• Even when listing the keys in the cache, and the keys appear in the body, it might be a good idea to list the keys as relative URIs (therefore percent-encoded)
• The values only appear in the request/response body, so they should not be encoded at all