message: Add doc and message on assertion
diff: @@ -33,9 +33,21 @@ impl CoordTransform {
  })
  }
  + /// Transform coordinates in place.
  + ///
  + /// # Arguments
  + /// * x - slice of x coordinates
  + /// * y - slice of y coordinates (must match x in length)
  + /// * z - slice of z coordinates, or an empty slice to ignore
  pub fn transform_coords(&self, x: &mut [f64], y: &mut [f64], z: &mut [f64]) -> Result<()> {
  let nb_coords = x.len();
  - assert_eq!(nb_coords, y.len());
  + assert_eq!(
  + nb_coords,
  + y.len(),
  + "transform coordinate slices have different length: {} != {}",
  + nb_coords,
  + y.len()
  + );
  let ret_val = unsafe {
  gdal_sys::OCTTransform(
  self.inner,
  @@ -45,7 +57,13 @@ impl CoordTransform {
  if z.is_empty() {
  null_mut()
  } else {
  - assert_eq!(nb_coords, z.len());
  + assert_eq!(
  + nb_coords,
  + z.len(),
  + "transform coordinate slices have different length: {} != {}",
  + nb_coords,
  + z.len()
  + );
  z.as_mut_ptr()
  },
  ) == 1
  