Dynamic setting of params in speckle filter

Done previously by berend-kupers, but removed during code review because
we thought it needed a separate node inside the filter. Here we use the
params_interface_ member variable of the filter base class instead of
creating a new node.

The callback needs to be post_set_params and not on_set_params because
the changes haven't been finalized yet when on_set_params is called.

include/laser_filters/speckle_filter.h

@@ -214,6 +214,9 @@ class LaserScanSpeckleFilter : public filters::FilterBase<sensor_msgs::msg::Lase
         break;
     }
 
+    post_set_parameters_callback_handle_ = params_interface_->add_post_set_parameters_callback(
+            std::bind(&LaserScanSpeckleFilter::reconfigureCB, this, std::placeholders::_1));
+
     return true;
   }
   /////////////////////////////////////////////////////
@@ -248,11 +251,8 @@ class LaserScanSpeckleFilter : public filters::FilterBase<sensor_msgs::msg::Lase
     return true;
   }
 
-  rcl_interfaces::msg::SetParametersResult reconfigureCB(std::vector<rclcpp::Parameter> parameters)
+  void reconfigureCB(std::vector<rclcpp::Parameter> parameters)
   {
-      auto result = rcl_interfaces::msg::SetParametersResult();
-      result.successful = true;
-
       for (auto parameter : parameters)
       {
         if(logging_interface_ != nullptr)
@@ -289,9 +289,6 @@ class LaserScanSpeckleFilter : public filters::FilterBase<sensor_msgs::msg::Lase
       default:
         break;
     }
-
-    return result;
-
   }
 
   ////////////////////////////////////////////////////
@@ -303,6 +300,7 @@ class LaserScanSpeckleFilter : public filters::FilterBase<sensor_msgs::msg::Lase
   double max_range = 0;
   double max_range_difference = 0;
   int filter_window = 0;
+  rclcpp::node_interfaces::PostSetParametersCallbackHandle::SharedPtr post_set_parameters_callback_handle_;
 };
 }
 #endif /* speckle_filter.h */