"trigger another selection round by blocking write operation");
ChannelWriter channelWriter = testChannelHandler.getChannelWriter();
StringToByteBufferTransformer transformer =
new StringToByteBufferTransformer();
transformer.setNextForwarder(channelWriter);
transformer.forward(
"this must block and trigger another selection round");
logger.finest("push dispatcher some selection rounds forward");
// (we REALLY need two calls here as the first round does not have the
// incomplete write in its selected set...)