@Test
  void propagatesDoubleNestedIOE() throws IOException {
    assertThatExceptionOfType(ConnectException.class)
        .isThrownBy(
            () -> {
              RibbonClient.propagateFirstIOException(
                  new ClientException(new RuntimeException(new ConnectException())));
            });
  }
Happened in practice; a blocking observable wrapped the connect exception in a runtime
exception
ribbon/src/test/java/feign/ribbon/PropagateFirstIOExceptionTest.java