public static @NonNull Throwable unwrapCompletionException(final @NonNull Throwable throwable) {
        if (throwable instanceof CompletionException) {
            return unwrapCompletionException(throwable.getCause());
        }
        return throwable;
    }
Unwraps a {@link CompletionException} recursively until a cause is encountered that is not a completion exception.

@param throwable the throwable
@return the original cause
cloud-core/src/main/java/org/incendo/cloud/exception/handling/ExceptionController.java