@Override
      public String toString() {
        StringBuilder builder = new StringBuilder(500);
        OutputStream os = new OutputStream() {
          @Override
          public void write(int i) {
            builder.append((char) i);
          }
        };
        PrintStream stream = new PrintStream(os);
        exception.printStackTrace(stream);
        return builder.toString();
      }
ExceptionWrapper is used in debugging hangs in waitForCurrentOperations(). It captures the
call stack of a thread invoking startOperation().
geode-core/src/main/java/org/apache/geode/distributed/internal/DistributionAdvisor.java