Just two trivial compiler warnings that are unrelated to the changes
made here.

Currently the BP `futures` tests rely on `std`. In order to actually
have them run, we should enable `std`, i.e., remove
`--no-default-features`.

Unfortunately, the RAII types used by `RwLock` are not `Send`, which is
why they can't be held over `await` boundaries. In order to allow
asynchronous events processing in multi-threaded environments, we here
allow to process events without holding the `total_consistency_lock`.