docs: function hrtimeAccum(a, b)
  {
  	assertHrtime(a);
  	assertHrtime(b);
  
  	/*
  	 * Accumulate the nanosecond component.
  	 */
  	a[1] += b[1];
  	if (a[1] >= 1e9) {
  		/*
  		 * The nanosecond component overflowed, so carry to the seconds
  		 * field.
  		 */
  		a[0]++;
  		a[1] -= 1e9;
  	}
  
  	/*
  	 * Accumulate the seconds component.
  	 */
  	a[0] += b[0];
  
  	return (a);
  }