[Storage Gateway] Journal Writer Implementation

[yinweiishere]

Implement journal writer to interact with IO hooker and DR server.

status:

1. scenario confirmed;
2. development kit: c++;
3. deployment: part of storage gateway client process, together with journal replayer;

[yinweiishere]

status: Hang due to integration work

plan: Implement framework

[yinweiishere]

status: framework patch committed

plan: write sequence graph, to check async/sync IO; confirm message head with jing, make message parser; ramp up with grpc, implement grpc client;

[liuanwang]

status: write sequence graph Done confirm message head with jing, make message parser Done

plan: ramp up with grpc, implement grpc client; implement worker thread and journal writer class

[liuanwang]

status: implement journal writer class 80%

plan: finish journal writer class discuss configuration and parse config.ini

[liuanwang]

status: implement journal writer class Done discuss configuration Done

plan: parse config.ini Research on the use of which crc algorithm

[liuanwang]

status: Research on the use of which crc algorithm Done

plan: implement pre_processor class

[liuanwang]

status: implement pre_processor class Done

plan: Debug journal_server write request

[liuanwang]

status: Debug journal_server write request Done

plan: Add unix domain socket and add send reply thread