Summary: Sometimes we don't know for sure if `ContextContainer` has a value or not (and that's perfectly legit use case). In those cases now we can use `findInstance` method that returns an optional intead of throwing an exeption.
Reviewed By: JoshuaGross
Differential Revision: D15039137
fbshipit-source-id: 95ba8cc7b76e37d1bd17e18c0098e56350ff3fef
Summary: Additional check verifies that requested type matches the type of a stored value.
Reviewed By: mdvacca
Differential Revision: D14944336
fbshipit-source-id: 6d3a1654d9b9a64ced83f553236093f02f2c97c7