add some data in RpcClientchannel
 add SentSession
 add checkstatus request
 implement
 implement
 disable heart-beat
 fix samll errof
 fix small error
fixbug: some code cannot be running on lower gcc
 add compress seg
 add counter for RpcClientChannel
 add comment
 fixbug: use ::base::PseudoRandom as thread-safe
 ISSUE 33
 implment func
 change error
 .
 .
 add new unittest
 add log