Users may want to remove an entry from a channel for various reasons. Since #4 tracking read state means we now have referenceable entry IDs, we can use those to also remove entries from a channel.
Here is what I've implemented in Aperture:
POST /microsub action=timeline &method=remove &entry=X
deletebecause the server may not actually delete the entry, for example if the feed is added to another channel, or to allow undos
entry- may be a single value or multiple values