Refactor socket peeker
Refactor socket peeker

Summary:
Refactor the socket peeker into its
own class so that it can be used in
other places as well, for example
for peeking at plaintext traffic.

Reviewed By: knekritz

Differential Revision: D3521899

fbshipit-source-id: fcd5615dd5d7cd1ddece4c624efbdecfbbc88a09

rklabs/folly,floxard/folly,facebook/folly,facebook/folly,Orvid/folly,Orvid/folly,facebook/folly,facebook/folly,rklabs/folly,rklabs/folly,floxard/folly,charsyam/folly,facebook/folly,rklabs/folly,floxard/folly,charsyam/folly,Orvid/folly,floxard/folly,floxard/folly,charsyam/folly,Orvid/folly,rklabs/folly,charsyam/folly,Orvid/folly