client expiring filter
client expiring filter

Summary: Use the expiring filter (i.e. idle timeout) in RpcClient

Test Plan: run rpc_client, should timeout after 5s of no activity.

Reviewed By: hans@fb.com

Subscribers: yfeldblum, fugalh, jsedgwick

FB internal diff: D2148616

Signature: t1:2148616:1434130194:5c404c8257be9a2116ee5a043c1d94b6f0adfcb4

raphaelamorim/wangle,facebook/wangle,Dalzhim/wangle,Orvid/wangle,facebook/wangle,AresTao/wangle,mzhaom/wangle,jamperry/wangle,Orvid/wangle,mzhaom/wangle,jamperry/wangle,raphaelamorim/wangle,AresTao/wangle,Dalzhim/wangle,facebook/wangle