Non-fatal Rpc error - connection left open for future rpc calls.

Fatal Server side Rpc error - connection closed.

* The connection context is sent as part of the connection establishment.

* This message is the header for the Protobuf Rpc Engine when sending a RPC request from RPC client to the RPC server.

* Rpc Response Header +------------------------------------------------------------------+ | Rpc total response length in bytes (4 bytes int) | | (sum of next two parts) | +------------------------------------------------------------------+ | RpcResponseHeaderProto - serialized delimited ie has len | +------------------------------------------------------------------+ | if request is successful: | | - RpcResponse - The actual rpc response bytes follow | | the response header | | This response is serialized based on RpcKindProto | | if request fails : | | The rpc response header contains the necessary info | +------------------------------------------------------------------+ Note that rpc response header is also used when connection setup fails.

* Security token identifier.

* Spec for UserInformationProto is specified in ProtoUtil#makeIpcConnectionContext.

* RpcKind determine the rpcEngine and the serialization of the rpc request.