Declare support for a 'CLIENT_OPTIONS' startup key.
This key is meant to be used by drivers for sending client-specific
configurations like request timeouts values, retry policy configuration, etc.
The value of this key can be any string in general (according to the CQL binary protocol),
however, it's expected to be some structured format, e.g. JSON.
Signed-off-by: Vlad Zolotarov <vladz@scylladb.com>
ea95cdaaec