public String readIfAvailable() {
            StringBuilder b = new StringBuilder();
            while (content.available()>0) {
                ByteBuffer nextBuffer = content.read();
                b.append(Charset.forName("utf-8").decode(nextBuffer));
            }
            return b.toString();
        }
Consumes all <i>currently</i> available data, or returns "" if no data is available right now. Never blocks.
container-core/src/main/java/com/yahoo/container/jdisc/RequestHandlerTestDriver.java