@CheckReturnValue
    protected final boolean tryEmit(int ordinal, @Nonnull Object item) {
        return outbox.offer(ordinal, item);
    }
@Test
    public void when_tryEmitTo1_then_emittedTo1() {
        // When
        boolean emitted = p.tryEmit(ORDINAL_1, MOCK_ITEM);

        // Then
        assertTrue(emitted);
        validateReceptionAtOrdinals(MOCK_ITEM, ORDINAL_1);
    }