Summary:
This change isolates the usage of folly async from Flipper. Is now self-contained in Flipper Folly schedulers.
Users of Flipper can decide not to use the types defined in that header and implement their own.
NOTE: changes are minimal, we are just replacing direct calls to folly event base with a scheduler which simply relays this on to folly.
Reviewed By: fabiomassimo
Differential Revision: D36052198
fbshipit-source-id: 170d64a324a1f1f100224e2622a59cbac3c8b642
ade685c621