public Plc4xEmbeddedChannel flushInbound() {
        flushInbound(true, voidPromise());
        return this;
    }
Flushes the inbound of this {@link Channel}. This method is conceptually equivalent to {@link #flush()}.

@see #flushOutbound()
plc4j/transports/test/src/main/java/io/netty/channel/embedded/Plc4xEmbeddedChannel.java