public String readAll() {
            String next;
            StringBuilder responseString = new StringBuilder();
            while (null != (next = read()) )
                responseString.append(next);
            return responseString.toString();
        }
Reads all data that will ever be produced by the channel attached to this, blocking as necessary.
Returns an empty string if there is no data.
container-core/src/main/java/com/yahoo/container/jdisc/RequestHandlerTestDriver.java