Add test coverage for SimpleRpcServer.
Improve the way we test both SimpleRpcServer and NettyRpcServer. Use
LoadTestKVGenerator to generate random values with varying sizes between
1000 bytes and 1M bytes, and also to verify them when reading the values
back.
Add secure test coverage for both SimpleRpcServer and NettyRpcServer.
Signed-off-by: Duo Zhang <zhangduo@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>