This is a follwup to the pre Foxy Message API review

If the point cloud is unordered, is row_step the length of data?

Comment: point_step seems to assumes a fields for a point are adjacent. What if the source data actually has each channel adjacent (all x values, then all y values, then all z values, then all intensities, etc)? Does the data need to be reordered to fit in this message?

What are the possible names of point field? I've seen x, y, z, xyz before, but I don't know of any documentation about those being standard.

https://github.com/ros2/common_interfaces/pull/86/files#diff-4fa5d39b533930879a61949f36d238cbR231