docs: public static SpannerException newSpannerException(@Nullable Context context, Throwable cause) {
      if (cause instanceof SpannerException) {
        SpannerException e = (SpannerException) cause;
        return newSpannerExceptionPreformatted(e.getErrorCode(), e.getMessage(), e);
      } else if (cause instanceof CancellationException) {
        return newSpannerExceptionForCancellation(context, cause);
      } else if (cause instanceof ApiException) {
        return fromApiException((ApiException) cause);
      }
      // Extract gRPC status.  This will produce "UNKNOWN" for non-gRPC exceptions.
      Status status = Status.fromThrowable(cause);
      if (status.getCode() == Status.Code.CANCELLED) {
        return newSpannerExceptionForCancellation(context, cause);
      }
      return newSpannerException(ErrorCode.fromGrpcStatus(status), cause.getMessage(), cause);
    }