@Override
    protected String throwableProxyToString(IThrowableProxy tp) {
        final String prefixed = PATTERN.matcher(super.throwableProxyToString(tp)).replaceAll(PREFIX);
        return CAUSING_PATTERN.matcher(prefixed).replaceAll(CAUSING);
    }
@Test
    void prefixesExceptionsWithExclamationMarks()  {
        assertThat(converter.throwableProxyToString(proxy).split("\\R"))
                .filteredOn(Objects::nonNull)
                .filteredOn(s -> !s.isEmpty())
                .isNotEmpty()
                .allSatisfy(line -> assertThat(line).startsWith("!"));
    }