fix detachPipeline/attachPipeline ordering
Summary:
detachPipeline always goes bottom to top
attachPipeline always goes top to bottom
now we can attachReadCallback in AsyncSocketHandler::attachPipeline()
not sure of the implications for TAsyncTransportHandler... looks like Cpp2Channel still wants to attach/detach cb manually
Test Plan: unit
Reviewed By: davejwatson@fb.com
Subscribers: fugalh, folly-diffs@, jsedgwick, yfeldblum, chalfant
FB internal diff:
D2023982
Tasks:
6836580
Signature: t1:
2023982:
1430157500:
e09a4103550a3e5721effaa1b28ac5bed071fa67