This `as? T` instruction warns that this is an unchecked cast.
It's unchecked in the literal sense : the compiler actually
doesn't check that the var is of that type. Accordingly, this
will only fail if `it` is null, which never happens.
Concretely what that means is that Java code calling this
method like
expect(AVAILABLE, network)
...will actually pass for *any* callback matching the network,
because the class is not checked.
Thankfully this code is recent and there doesn't seem to be a
lot of tests that got accepted by this bug when they should
have been rejected.
Test: ConnectivityServiceTest, TH
new test in this patch that fails before but succeeds after
Change-Id: I2e48dae28ff92045f002cfb2798d383c9c19d5ed