Details
Description
Servers have the ability to handle custom rpc priority levels, but currently we are only using it to differentiate META/ROOT updates from replication and other 'priority' updates (as specified by annotation tags per RS method).
However, some clients need the ability to create custom handlers (e.g. PHOENIX-938) which can really only be cleanly tied together to requests by the request priority. The disconnect is in that there is no way for the client to overwrite the priority per table - the PayloadCarryingRpcController will always just set priority per ROOT/META and otherwise just use the generic priority.