presto-main/src/main/java/io/prestosql/operator/SpilledLookupSourceHandle.java/SpilledLookupSourceHandle/assertState
class SpilledLookupSourceHandle:    @GuardedBy("this")
    private void assertState(State expectedState)
    {
        State currentState = state;
        checkState(currentState == expectedState, "Expected state %s, but state is %s", expectedState, currentState);
    }