subscribe to any topic of any type and get received messages as a raw vector of bytes

[lucasw]

Description

Subscribe to a topic without needing to know the type, and then get the received message as a raw vector of bytes, similar to rospy AnyMsg and roscpp ShapeShifter.

This isn't quite what was suggested in #190 (comment) I couldn't figure out how to make a function within the existing Subscriber that can do different things depending on type, it needs specialization? Is having both a Subscriber and SubscriberAny bad for other parts of roslibrust?

Fixes

Closes: #190

Checklist

• [ ✔️ ] Update CHANGELOG.md

[Carter12s]

I'm not opposed to this as the solution, and I think having this in the crate is better than not having anything, so I'm okay with merging this.

The part where this can get messy is with the TopicProvider trait I'm working on now. Having SubscriberAny just makes it hard (not impossible) to create a generic trait that represents a ROS api. It adds another generic associated type on the trait, but that is probably fine?

If you are interested I'd be happy to throw together a version of what I was think of, and we could compare them?

Otherwise happy to merge this as is (once Drop stuff is fixed).

[lucasw]

I'm not opposed to this as the solution, and I think having this in the crate is better than not having anything, so I'm okay with merging this.

The part where this can get messy is with the TopicProvider trait I'm working on now. Having SubscriberAny just makes it hard (not impossible) to create a generic trait that represents a ROS api. It adds another generic associated type on the trait, but that is probably fine?

If you are interested I'd be happy to throw together a version of what I was think of, and we could compare them?

Otherwise happy to merge this as is (once Drop stuff is fixed).

I suppose just unwind any amount of this once topic provider is ready?

I also have a publisher any commit I could add here, it's very similar.

But if topic provider is very close this doesn't need to be merged.

[Carter12s]

If you have publisher any ready, go ahead and put PR up. TopicProvider stuff can take a back seat!