code: private Throwable wrapCancellationException(Throwable u) {
          Throwable wrappedException = null;
          if (u != null) {
              wrappedException = Exceptions.unwrap(u);
              if (wrappedException instanceof CancellationException) {
                  wrappedException = new ReadCancellationException(wrappedException);
              }
          }
          return wrappedException;
      }
docs: Wrap a {@link CancellationException} to {@link ReadCancellationException}