The keyval package defines the client API to access a key-value data
store. It comprises two sub-APIs: the Broker interface supports reading
and manipulation of key-value pairs; the Watcher API provides functions
for monitoring of changes in a data store. Both interfaces are available
with arguments of type []bytes (raw data) and proto.Message (protobuf
formatted data).
The keyval package also provides a skeleton for a key-value plugin.
A particular data store is selected in the NewSkeleton constructor
using an argument of type CoreBrokerWatcher. The skeleton handles
the plugin's life-cycle and provides unified access to datastore
implementing the KvPlugin interface.