docs: public static double logpoissonPDFm1(double x_plus_1, double lambda) {
      if(Double.isInfinite(lambda)) {
        return Double.NEGATIVE_INFINITY;
      }
      if(x_plus_1 > 1) {
        return rawLogProbability(x_plus_1 - 1, lambda);
      }
      if(lambda > Math.abs(x_plus_1 - 1) * MathUtil.LOG2 * Double.MAX_EXPONENT / 1e-14) {
        return -lambda - GammaDistribution.logGamma(x_plus_1);
      }
      else {
        return rawLogProbability(x_plus_1, lambda) + FastMath.log(x_plus_1 / lambda);
      }
    }