Summary:
AsyncSSLSocket's eorAwareBioWrite does some invasive stuff like
reaching into a BIO and replacing its method (and the 'write' funcptr). This
approach won't work with OpenSSL 1.1.0 or BoringSSL due to API changes and
structs being made opaque. This diff adds a layer of wrappers for some BIO
operations. Note that this is still only tested on 1.0.2

Reviewed By: siyengar

Differential Revision: D3338861

fbshipit-source-id: 2ac9318b0df1709873511bfde0fa85d87c5dd29a